Reference:

J. Esparza and M. Silva. On the analysis und synthesis of free choice systems. In G Rozenberg., editor, Advances in Petri Nets 1990, number 483 in Lecture Notes in Computer Science, pages 243–286, 1990.

Suggested BibTeX entry:

@inproceedings{ES90a,
    author = {J. Esparza and M. Silva},
    booktitle = {Advances in {P}etri Nets 1990},
    editor = {G Rozenberg.},
    number = {483},
    pages = {243--286},
    series = {Lecture Notes in Computer Science},
    title = {On the Analysis und Synthesis of Free Choice Systems},
    year = {1990}
}