Reference:

J. Esparza. A polynomial-time algorithm for checking consistency of free-choice signal transition graphs. Fundamenta Informaticae, 62(2):197–220, 2004.

Suggested BibTeX entry:

@article{Esp04,
    author = {J. Esparza},
    journal = {Fundamenta Informaticae},
    number = {2},
    pages = {197--220},
    title = {A Polynomial-Time Algorithm for Checking Consistency of Free-Choice Signal Transition Graphs},
    volume = {62},
    year = {2004}
}