@incollection{howell:rosier:1987,
    Author = {Howell, Rodney R. and Rosier, LouisE.},
    BookTitle = {Advances in Petri Nets 1987},
    Editor = {Rozenberg, Grzegorz},
    File = {Recent results on the complexity of problems related to Petri nets - Howell, Rosier (0) (0) - a - a - w.pdf},
    ISBN = {978-3-540-18086-9},
    Keywords = {vector addition systems and Petri nets},
    Pages = {45-72},
    Publisher = {Springer Berlin Heidelberg},
    Series = {Lecture Notes in Computer Science},
    Title = {Recent results on the complexity of problems related to Petri nets},
    URL = {http://dx.doi.org/10.1007/3-540-18086-9\_19},
    Volume = {266},
    Year = {1987},
    bdsk-url-1 = {http://dx.doi.org/10.1007/3-540-18086-9\_19},
    date-added = {2013-11-11 14:00:42 +0000},
    date-modified = {2013-11-11 14:00:57 +0000},
    doi = {10.1007/3-540-18086-9_19}
}

@incollection{howell:rosier:1987, Author = {Howell, Rodney R. and Rosier, LouisE.}, BookTitle = {Advances in Petri Nets 1987}, Editor = {Rozenberg, Grzegorz}, File = {Recent results on the complexity of problems related to Petri nets - Howell, Rosier (0) (0) - a - a - w.pdf}, ISBN = {978-3-540-18086-9}, Keywords = {vector addition systems and Petri nets}, Pages = {45-72}, Publisher = {Springer Berlin Heidelberg}, Series = {Lecture Notes in Computer Science}, Title = {Recent results on the complexity of problems related to Petri nets}, URL = {http://dx.doi.org/10.1007/3-540-18086-9_19}, Volume = {266}, Year = {1987}, bdsk-url-1 = {http://dx.doi.org/10.1007/3-540-18086-9_19}, date-added = {2013-11-11 14:00:42 +0000}, date-modified = {2013-11-11 14:00:57 +0000}, doi = {10.1007/3-540-18086-9_19} }