Reference:

J. Esparza and M. Silva. Circuits, handles, bridges and nets. In G. Rozenberg, editor, Advances in Petri Nets 1990, number 483 in Lecture Notes in Computer Science, pages 210–242, 1990.

Suggested BibTeX entry:

@inproceedings{ES90b,
    author = {J. Esparza and M. Silva},
    booktitle = {Advances in {P}etri Nets 1990},
    editor = {G.~Rozenberg},
    number = {483},
    pages = {210--242},
    series = {Lecture Notes in Computer Science},
    title = {Circuits, Handles, Bridges and Nets},
    year = {1990}
}