@article{DBLP:journals/jacm/FellowsL88,
author = {Michael R. Fellows and
Michael A. Langston},
title = {Nonconstructive tools for proving polynomial-time decidability},
journal = {J. ACM},
volume = {35},
number = {3},
year = {1988},
pages = {727-739},
ee = {http://doi.acm.org/10.1145/44483.44491},
bibsource = {DBLP, http://dblp.uni-trier.de}
}