Research reports

Kaj Holmberg. On Using OpenStreetMap and GPS for Optimization. Research Report LiTH-MAT-R-2015/15-SE, Department of Mathematics, Linkoping Institute of Technology, Sweden, 2015.

Kaj Holmberg. Heuristics for the weighted k-Chinese/rural postman problem with a hint of fixed costs with applications to urban snow removal. Research Report LiTH-MAT-R-2015/13-SE, Department of Mathematics, Linkoping Institute of Technology, Sweden, 2015.

Kaj Holmberg. Computational Results for Map Matching by Optimization. Research Report LiTH-MAT-R-2015/02-SE, Department of Mathematics, Linkoping Institute of Technology, Sweden, 2015.

Kaj Holmberg. Map Matching by Optimization. Research Report LiTH-MAT-R-2015/01-SE, Department of Mathematics, Linkoping Institute of Technology, Sweden, 2015.

Kaj Holmberg. Formation of Student Groups with the Help of Optimization. Research Report LiTH-MAT-R-2014/14-SE, Department of Mathematics, Linkoping Institute of Technology, Sweden, 2014.

Kaj Holmberg. Urban Snow Removal: Modeling and Relaxations. Research Report LiTH-MAT-R-2014/08-SE, Department of Mathematics, Linkoping Institute of Technology, Sweden, 2014.

Nils-Hassan Quttineh, Kristian Lundberg, Kaj Holmberg and Torbjörn Larsson. Aircraft Mission Planning. Research Report LiTH-MAT-R-2012/07-SE, Department of Mathematics, Linkoping Institute of Technology, Sweden, 2012.

Nils-Hassan Quttineh, Kristian Lundberg, Kaj Holmberg and Torbjörn Larsson. Effect Oriented Planning. Research Report LiTH-MAT-R-2012/06-SE, Department of Mathematics, Linkoping Institute of Technology, Sweden, 2012.

Oleg Burdakov, Patrick Doherty, Kaj Holmberg and Per-Magnus Olsson. Optimal Placement of Communications Relay Nodes. Research Report LiTH-MAT-R-2009-03, Department of Mathematics, Linkoping Institute of Technology, Sweden, 2009.

Oleg Burdakov, Kaj Holmberg and Per-Magnus Olsson. A Dual Ascent Method for the Hop-Constrained Shortest Path Problem with Application to Positioning of Unmanned Aerial Vehicles. Research Report LiTH-MAT-R-2008-07, Department of Mathematics, Linkoping Institute of Technology, Sweden, 2008.

Kaj Holmberg. Heuristics for the Rural Postman Problem with Application to Snow Removal for Secondary Roads. Research Report LiTH-MAT-R-2008-14, Department of Mathematics, Linkoping Institute of Technology, Sweden, 2008.

Kaj Holmberg. Graph Optimization Approaches for Minimal Rerouting in Symmetric Three Stage Clos Network. Research Report LiTH-MAT-R-2007-12, Department of Mathematics, Linkoping Institute of Technology, Sweden, 2007.

Kaj Holmberg. Optimization Models for Routing in Switching Networks of Clos Type with Many Stages. Research Report LiTH-MAT-R-2007-11, Department of Mathematics, Linkoping Institute of Technology, Sweden, 2007.

Peter Broström and Kaj Holmberg. Design of OSPF Networks using Subpath Consistent Routing Patterns. Research Report LiTH-MAT-R-2007-05, Department of Mathematics, Linkoping Institute of Technology, Sweden, 2007.

Peter Broström and Kaj Holmberg. Compatible Weights and Valid Cycles in Non-spanning OSPF Routing Patterns. Research Report LiTH-MAT-R-2007-04, Department of Mathematics, Linkoping Institute of Technology, Sweden, 2007.

Peter Broström and Kaj Holmberg. On the Extremal Structure of an OSPF Related Cone. Research Report LiTH-MAT-R-2006-02, Department of Mathematics, Linkoping Institute of Technology, Sweden, 2006.

Peter Broström and Kaj Holmberg. A New Derivation of Valid Cycles. Research Report LiTH-MAT-R-2005-03, Department of Mathematics, Linkoping Institute of Technology, Sweden, 2005.

Kaj Holmberg, Martin Joborn and Kennet Melin. Lagrangian Based Heuristics for the Multicommodity Network Flow Problem with Fixed Costs on Paths. Research Report LiTH-MAT-R-2004-15, Department of Mathematics, Linkoping Institute of Technology, Sweden, 2004.

Kaj Holmberg. Mean Value Cross Decomposition Based Branch-and-Bound for Mixed Integer Programming Problems. Research Report LiTH-MAT-R-2004-13, Department of Mathematics, Linkoping Institute of Technology, Sweden, 2004.

Peter Broström and Kaj Holmberg. Stronger Necessary Conditions for the Existence of a Compatible OSPF Metric. Research Report LiTH-MAT-R-2004-08, Department of Mathematics, Linkoping Institute of Technology, Sweden, 2004.

Peter Broström and Kaj Holmberg. Determining the Non-Existence of a Compatible OSPF Metric. Research Report LiTH-MAT-R-2004-06, Department of Mathematics, Linkoping Institute of Technology, Sweden, 2004.

Peter Broström and Kaj Holmberg. Multiobjective Design of Survivable IP Networks. Research Report LiTH-MAT-R-2004-03, Department of Mathematics, Linkoping Institute of Technology, Sweden, 2004.

M. Henningsson, K. Holmberg, M. Rönnqvist and P. Värbrand. A Column Generation Approach for a Ring Network Design Problem. Research Report LiTH-MAT-R-2003-21, Department of Mathematics, Linkoping Institute of Technology, Sweden, 2003.

M. Henningsson, K. Holmberg, M. Rönnqvist and P. Värbrand. A Ring Network Design Problem Solved by a Ring Generation and Allocation Approach. Research Report LiTH-MAT-R-2003-20, Department of Mathematics, Linkoping Institute of Technology, Sweden, 2003.

Mathias Henningsson and Kaj Holmberg. A Ring Generation Problem Based on the Traveling Salesman Subtour Problem. Research Report LiTH-MAT-R-2003-19, Department of Mathematics, Linkoping Institute of Technology, Sweden, 2003.

Mathias Henningsson and Kaj Holmberg. Calculating Cost Coefficients for Generation of Rings in Network Design. Research Report LiTH-MAT-R-2003-18, Department of Mathematics, Linkoping Institute of Technology, Sweden, 2003.

Mathias Henningsson and Kaj Holmberg. Lagrangean Price Directive Ring Generation for Network Design. Research Report LiTH-MAT-R-2003-17, Department of Mathematics, Linkoping Institute of Technology, Sweden, 2003.

M. Henningsson, K. Holmberg, M. Rönnqvist and P. Värbrand. A Ring Network Design Problem and Heuristics for Generating a Set of Feasible Rings. Research Report LiTH-MAT-R-2003-16, Department of Mathematics, Linkoping Institute of Technology, Sweden, 2003.

Kaj Holmberg and Krzysztof Kiwiel. Mean Value Cross Decomposition for Nonlinear Convex Problems. Research Report LiTH-MAT-R-2003-10, Department of Mathematics, Linkoping Institute of Technology, Sweden, 2003.

Teodor Crainic, Michel Gendreau, Kaj Holmberg, Martin Joborn and Jan Lundgren. Economies of Scale in Empty Freight Car Distribution in Scheduled Railways. CRT-2002-48. Centre for Research on Transportation, Universite de Montreal, Canada.

Teodor Crainic, Michel Gendreau, Kaj Holmberg, Martin Joborn and Jan Lundgren. Economies of Scale in Empty Freight Car Distribution in Scheduled Railways. CRT-2001-12. Centre for Research on Transportation, Universite de Montreal, Canada.

Kim Allan Andersen, Anders J.V. Skriver and Kaj Holmberg. Bicriteria Network Location (BNL) Problems with Criteria Dependent Lengths and Minisum Objectives Research Report LiTH-MAT-R-2001-10, Department of Mathematics, Linkoping Institute of Technology, Sweden, 2001.

Kaj Holmberg and Di Yuan. Optimization of Internet Protocol Network Design and Routing Research Report LiTH-MAT-R-2001-07, Department of Mathematics, Linkoping Institute of Technology, Sweden, 2001.

Teodor Crainic, Michel Gendreau, Kaj Holmberg, Martin Joborn and Jan Lundgren. Economies of Scale in Empty Freight Car Distribution in Scheduled Railways. Working Paper LiTH-MAT-OPT/WP-1999-01, Department of Mathematics, Linkoping Institute of Technology, Sweden, 1999.

Mathias Henningsson, Kaj Holmberg and Mikael Domander (previously Näsberg). A Capacitated Bus Grid Network Design Problem. Research Report LiTH-MAT-R-1998-10, Department of Mathematics, Linkoping Institute of Technology, Sweden, 1998.

Kaj Holmberg and Di Yuan. Network Optimization within the Telecommunication Area: A Literature Survey. Working Paper LiTH-MAT-OPT/WP-1998-01, Linkoping Institute of Technology, Sweden, 1998.

Mathias Henningsson, Kaj Holmberg, Mikael Näsberg and Di Yuan. Cost-Efficient Bandwidth Expansion of a Cable TV Network for Interactive Broadband Services. Working Paper LiTH-MAT-OPT/WP-1998-02, Department of Mathematics, Linkoping Institute of Technology, Sweden, 1998.

Mathias Henningsson, Kaj Holmberg, Mikael Rönnqvist and Peter Värbrand. A Ring Network Design Problem. Working Paper LiTH-MAT-OPT/WP-1998-03, Department of Mathematics, Linkoping Institute of Technology, Sweden, 1998.

Kaj Holmberg and Di Yuan. A Multicommodity Network Flow Problem with Side Constraints on Paths Solved by Column Generation. Research Report LiTH-MAT-R-1998-05, Department of Mathematics, Linkoping Institute of Technology, Sweden, 1998.

Kaj Holmberg and Di Yuan. A Lagrangean Approach to Network Design Problems. Research Report LiTH-MAT-R-1998-01, Department of Mathematics, Linkoping Institute of Technology, Sweden, 1998.

Kaj Holmberg. Creative Modeling: Variable and Constraint Duplication in Primal-Dual Decomposition Methods. Research Report LiTH-MAT-R-1997-08, Department of Mathematics, Linkoping Institute of Technology, Sweden, 1997.

Kaj Holmberg, Mikael Rönnqvist and Di Yuan. Solving Capacitated Facility Location Problems with Single Sourcing Using Lagrangean Heuristics, Repeated Matching and Branch-and-Bound. Research Report LiTH-MAT-R-1997-05, Department of Mathematics, Linkoping Institute of Technology, Sweden, 1997.

Patrik Flisberg, Kaj Holmberg, Martin Joborn and Jan Lundgren. A Model for Dimensioning of Transportation Capacities in a Railway Network. Research Report LiTH-MAT-R-1996-27, Department of Mathematics, Linkoping Institute of Technology, Sweden, 1996.

Kaj Holmberg and Di Yuan. A Lagrangean Heuristic Based Branch-and-Bound Approach for the Capacitated Network Design Problem. Research Report LiTH-MAT-R-1996-23, Department of Mathematics, Linkoping Institute of Technology, Sweden, 1996.

Kaj Holmberg, Martin Joborn and Jan Lundgren. A Model for Distribution of Empty Freight Cars. Research Report LiTH-MAT-R-1996-11, Department of Mathematics, Linkoping Institute of Technology, Sweden, 1996.

Kaj Holmberg. Exact Solution Methods for Uncapacitated Location Problems with Convex Transportation Costs. Research Report LiTH-MAT-R-1996-10, Department of Mathematics, Linkoping Institute of Technology, Sweden, 1996.

Kaj Holmberg. Lagrangean Heuristics for Linear Cost Multicommodity Network Flow Problems. Working Paper LiTH-MAT-OPT/WP-1995-01, Department of Mathematics, Linkoping Institute of Technology, Sweden, 1995.

Kaj Holmberg and Jonas Ling. A Lagrangean Heuristic for the Facility Location Problem with Staircase Costs. Research Report LiTH-MAT-R-1995-24, Department of Mathematics, Linkoping Institute of Technology, Sweden, 1995.

Kaj Holmberg. Experiments with primal-dual decomposition and subgradient methods for the uncapacitated facility location problem. Research Report LiTH-MAT/OPT-WP-1995-08, Optimization, Department of Mathematics, Linkoping Institute of Technology, Sweden, 1995.

Kaj Holmberg and Kurt Jornsten. Decomposition methods for the exact formulation of the simple plant location problem with spatial interaction. Research Report LiTH-MAT/OPT-WP-1995-13, Optimization, Department of Mathematics, Linkoping Institute of Technology, Sweden, 1995.

Johan Hellstrand and Kaj Holmberg. A Lagrangean heuristic applied to the uncapacitated network design problem. Working Paper LiTH-MAT/OPT-WP-1994-01, Department of Mathematics, Linkoping Institute of Technology, Sweden, 1994.

Kaj Holmberg and Johan Hellstrand. Solving the uncapacitated network design problem by a Lagrangean heuristic and branch-and-bound. Research Report LiTH-MAT-R-1994-11, Department of Mathematics, Linkoping Institute of Technology, Sweden, 1994.

Kaj Holmberg and Kurt Jornsten. A dual ascent procedure for the exact formulation of the simple plant location problem with spatial interaction. Research Report LiTH-MAT/OPT-WP-1994-31, Optimization, Department of Mathematics, Linkoping Institute of Technology, Sweden, 1994.

Kaj Holmberg and Kurt Jornsten. Dual search procedures for the exact formulation of the simple plant location problem with spatial interaction. Research Report LiTH-MAT/OPT-WP-1994-38, Optimization, Department of Mathematics, Linkoping Institute of Technology, Sweden, 1994.

Kaj Holmberg and Kurt Jornsten. A simple modification of Dantzig-Wolfe decomposition. Research Report LiTH-MAT-R-1994-04, Optimization, Department of Mathematics, Linkoping Institute of Technology, Sweden, 1994. Accepted for publication in Optimization.

Kaj Holmberg. Primal and dual decomposition as organizational design: Price and/or resource directive decomposition. Research Report LiTH-MAT-R-1994-03, Department of Mathematics, Linkoping Institute of Technology, Sweden, 1994.

Kaj Holmberg. Computational tests of decomposition and linearization methods for the stochastic transportation problem. Working Paper LiTH-MAT/OPT-WP-1993-01, Optimization, Department of Mathematics, Linkoping Institute of Technology, Sweden, 1993.

Kaj Holmberg. Efficient decomposition and linearization methods for the stochastic transportation problem. Research Report LiTH-MAT-R-1993-10, Department of Mathematics, Linkoping Institute of Technology, Sweden, 1993.

Kaj Holmberg and Hoang Tuy. A production-transportation problem with stochastic demand and concave production costs. Research Report LiTH-MAT-R-1993-30, Department of Mathematics, Linkoping Institute of Technology, Sweden, 1993.

Kaj Holmberg and Kurt Jornsten. Solving the generalized knapsack problem with variable coefficients. Working Paper LiTH-MAT/OPT-WP-1991-18, Department of Mathematics, Linkoping Institute of Technology, Sweden, 1993.

Kaj Holmberg and Kurt Jornsten. Solving the generalized knapsack problem with variable coefficients. Research Report LiTH-MAT-R-1993-19, Department of Mathematics, Linkoping Institute of Technology, Sweden, 1993.

Kaj Holmberg and Kurt Jornsten. Decomposition methods for the exact formulation of the simple plant location problem with spatial interaction. Working Paper LiTH-MAT/OPT-WP-1991-10, Optimization, Department of Mathematics, Linkoping Institute of Technology, Sweden, 1991.

Kaj Holmberg and Kurt Jornsten. A dual ascent procedure for the exact formulation of the simple plant location problem with spatial interaction. Working Paper LiTH-MAT/OPT-WP-1991-08, Optimization, Department of Mathematics, Linkoping Institute of Technology, Sweden, 1991.

Kaj Holmberg and Kurt Jornsten. The exact formulation of the simple plant location problem with spatial interaction and its solution. Working Paper LiTH-MAT/OPT-WP-1991-09, Optimization, Department of Mathematics, Linkoping Institute of Technology, Sweden, 1991.

Kaj Holmberg and Kurt Jornsten. A simple modification of Dantzig-Wolfe decomposition. Working Paper LiTH-MAT/OPT-WP-1991-02, Optimization, Department of Mathematics, Linkoping Institute of Technology, Sweden, 1991.

Kaj Holmberg. Applying mean value cross decomposition and other primal-dual solution methods to the uncapacitated facility location problem. Working Paper LiTH-MAT/OPT-WP-1991-11, Optimization, Department of Mathematics, Linkoping Institute of Technology, Sweden, 1991.

Kaj Holmberg. A convergence proof for linear mean value cross decomposition. Research Report LiTH-MAT-R-1991-09, Department of Mathematics, Linkoping Institute of Technology, Sweden, 1991. Revised verison of \citeKajRR90/12.

Kaj Holmberg. Generalized cross decomposition applied to nonlinear integer programming problems: Duality gaps and convexification in parts. Research Report LiTH-MAT-R-1991-13, Department of Mathematics, Linkoping Institute of Technology, Sweden, 1991.

Kaj Holmberg. Linearizations of the staircase cost facility location problem. Research Report LiTH-MAT-R-1991-19, Department of Mathematics, Linkoping Institute of Technology, Sweden, 1991.

Kaj Holmberg. Mean value cross decomposition applied to integer programming problems. Research Report LiTH-MAT-R-1991-18, Department of Mathematics, Linkoping Institute of Technology, Sweden, 1991.

Kaj Holmberg. Nonlinear mean value cross decomposition: The strictly convex case. Working Paper LiTH-MAT/OPT-WP-1991-15, Optimization, Department of Mathematics, Linkoping Institute of Technology, Sweden, 1991.

Kaj Holmberg. On using approximations of the Benders master problem. Working Paper LiTH-MAT/OPT-WP-1991-12, Optimization, Department of Mathematics, Linkoping Institute of Technology, Sweden, 1991.

Kaj Holmberg. Solving the staircase cost facility location problem with decomposition and piecewise linearization. Research Report LiTH-MAT-R-1991-20, Department of Mathematics, Linkoping Institute of Technology, Sweden, 1991.

Kaj Holmberg. Variable and constraint duplication techniques in primal-dual decomposition methods. Research Report LiTH-MAT-R-1991-23, Department of Mathematics, Linkoping Institute of Technology, Sweden, 1991.

Kaj Holmberg and A. Migdalas. Solution methods for the discrete choice network design problem combining Lagrangean relaxation and decomposition with generation of valid inequalitites. Working Paper LiTH-MAT/OPT-WP-1991-07, Optimization, Department of Mathematics, Linkoping Institute of Technology, Sweden, 1991.

Kaj Holmberg. Benders decomposition using approximations of the master problem compared to cross decomposition. Research Report 90/14, Operationsanalyse, Matematisk Institut, Aarhus University, Denmark, 1990.

Kaj Holmberg. A convergence proof for linear mean value cross decomposition. Research Report 90/12, Operationsanalyse, Matematisk Institut, Aarhus University, Denmark, 1990.

Kaj Holmberg. Cross decomposition applied to integer programming problems: Duality gaps and convexification in parts. Research Report LiTH-MAT-R-1990-34, Department of Mathematics, Linkoping Institute of Technology, Sweden, 1990.

Kaj Holmberg. Linear mean value cross decomposition: A generalization of the Kornai-Liptak method. Research Report 90/1, Operationsanalyse, Matematisk Institut, Aarhus University, Denmark, 1990.

Kaj Holmberg. Linear mean value cross decomposition: A generalization of the Kornai-Liptak method. Research Report LiTH-MAT-R-1990-39, Department of Mathematics, Linkoping Institute of Technology, Sweden, 1990. Revised version of \citeKajRR90/1.

Kaj Holmberg. Combining cross decomposition with the approach of Kornai and Liptak. Working Paper LiTH-MAT/OPT-WP-1989-06, Optimization, Department of Mathematics, Linkoping Institute of Technology, Sweden, 1989.

Kaj Holmberg. Computational experiments with primal-dual solution methods for the produce-or-purchase problem. Research Report LiTH-MAT-R-1989-20, Department of Mathematics, Linkoping Institute of Technology, Sweden, 1989.

Kaj Holmberg. Cross decomposition and Lagrangean relaxation of the Benders master problem. Research Report LiTH-MAT-R-1989-14, Department of Mathematics, Linkoping Institute of Technology, Sweden, 1989.

Kaj Holmberg. A note on Lagrangean relaxation of the Benders master problem. Research Report LiTH-MAT-R-1989-04, Department of Mathematics, Linkoping Institute of Technology, Sweden, 1989.

Kaj Holmberg. On the use of valid inequalities in Benders and cross decomposition. Research Report LiTH-MAT-R-1989-21, Department of Mathematics, Linkoping Institute of Technology, Sweden, 1989.

Kaj Holmberg. Solution methods for staircase cost problems based on convex piecewise linearization, Benders decomposition, Lagrangean relaxation and cross decomposition. Research Report LiTH-MAT-R-1989-15, Department of Mathematics, Linkoping Institute of Technology, Sweden, 1989.

Kaj Holmberg. Transportation and location problems with staircase costs. Research Report LiTH-MAT-R-1989-12, Department of Mathematics, Linkoping Institute of Technology, Sweden, 1989.

Kaj Holmberg. Generalized cross decomposition applied to the stochastic transportation-location problem. Research Report LiTH-MAT-R-1988-15, Department of Mathematics, Linkoping Institute of Technology, Sweden, 1988.

Kaj Holmberg. Generalized cross decomposition with variable and constraint duplication techniques. Research Report LiTH-MAT-R-1988-17, Department of Mathematics, Linkoping Institute of Technology, Sweden, 1988.

Kaj Holmberg. Primal-dual subgradient optimization and cross decomposition with applications to the produce-or-purchase problem. Research Report LiTH-MAT-R-1988-16, Department of Mathematics, Linkoping Institute of Technology, Sweden, 1988.

Kaj Holmberg. On the solving of large transportation problems. Working Paper LiTH-MAT/OPT-WP-1987-07, Optimization, Department of Mathematics, Linkoping Institute of Technology, Sweden, 1987.

Kaj Holmberg. On the convergence of cross decomposition. Research Report LiTH-MAT-R-1986-17, Department of Mathematics, Linkoping Institute of Technology, Sweden, 1986. (Revised 1988).

Kaj Holmberg, Kurt Jornsten, and A. Migdalas. Decomposition methods applied to discrete network design. Working Paper LiTH-MAT/OPT-WP-1986-07, Optimization, Department of Mathematics, Linkoping Institute of Technology, Sweden, 1986.

Kaj Holmberg, Kurt Jornsten, and X.Gui. Cross decomposition applied to a mathematical programming model for distribution planning of crude oil and petroleum products in China. Research Report LiTH-MAT-R-1984-01, Department of Mathematics, Linkoping Institute of Technology, Sweden, 1984.

Kaj Holmberg. Facility location with staircase costs. Research Report LiTH-MAT-R-1984-05, Department of Mathematics, Linkoping Institute of Technology, Sweden, 1984.

Kaj Holmberg. A useful tool for analysing and planning goods transportation. Research Report LiTH-MAT-R-1984-09, Department of Mathematics, Linkoping Institute of Technology, Sweden, 1984.

Kaj Holmberg. Separable programming applied to the stochastic transportation problem. Research Report LiTH-MAT-R-1984-15, Department of Mathematics, Linkoping Institute of Technology, Sweden, 1984.

Kaj Holmberg. Basic decomposition principles. Research Report LiTH-MAT-R-1984-17, Department of Mathematics, Linkoping Institute of Technology, Sweden, 1984.

Kaj Holmberg and Kurt Jornsten. Exact methods for gravity trip distribution models. Research Report LiTH-MAT-R-1984-19, Department of Mathematics, Linkoping Institute of Technology, Sweden, 1984.

Kaj Holmberg and Kurt Jornsten. Decomposition methods for relaxed gravity models. Research Report LiTH-MAT-R-1984-23, Department of Mathematics, Linkoping Institute of Technology, Sweden, 1984.

Kaj Holmberg. Capacitated facility location with staircase costs. Research Report LiTH-MAT-R-1984-26, Department of Mathematics, Linkoping Institute of Technology, Sweden, 1984.

Kaj Holmberg and Kurt Jornsten. Dual search procedures for trip distribution estimation. Research Report LiTH-MAT-R-1984-27, Department of Mathematics, Linkoping Institute of Technology, Sweden, 1984.

Kaj Holmberg and Kurt Jornsten. A mathematical programming model for furniture transportation planning. Working paper, Optimization, Department of Mathematics, Linkoping Institute of Technology, Sweden, 1983. In swedish.

Kaj Holmberg and Kurt Jornsten. Cross decomposition applied to the stochastic transportation problem. Research Report LiTH-MAT-R-1982-22, Department of Mathematics, Linkoping Institute of Technology, Sweden, 1982.

Kaj Holmberg <kaj.holmberg@liu.se>