The aim of these series of volumes "Advances in Petri Nets" is to present to the general computer science community the most significant recent results with regard to the development in the area. The main source of the papers are the annual European Workshops on Applications and Theory of Petri Nets"; the highest ranked papers from the past workshops are considered for the series, i.e., they are again reviewed and accordingly revised or extended. In addition to the workshop papers, the "Advances" also present invited papers. The present volume Advances in Petri Nets 1987 covers the 7th "European Workshop on Applications and Theory of Petri Nets" held in Oxford, Great Britain, in June 1986. It also contains a survey on complexity of problems related to Petri nets written by R.R. Howell and L.E. Rosier. A special feature of this volume is a bibliography on Petri nets, containing more than 2000 entries.

The main idea behind the series of volumes Advances in Petri Nets is to present to the general computer science community recent results which are the most representative and significant for the development of the area. Thepapers for the volumes are drawn mainly from the annual International Conferences on Applications and Theory of Petri Nets. Selected papers from the latest conference are independently refereed, and revised and extended as necessary. Some further papers submitted directly to the editor are included. Advances in Petri Nets 1991 covers the 11th International Conference on Applications and Theory of Petri Nets held in Paris, France in June 1991. The volume contains the Bibliography of Petri Nets 1990 prepared by H. Pl}nnecke and W. Reisig, with over 4000 entries.