@INPROCEEDINGS{PittsAM:polist,
 AUTHOR={A.~M.~Pitts},
 TITLE={Polymorphism Is Set Theoretic, Constructively},
 BOOKTITLE={Category Theory and Computer Science, 
 Proc.\ Edinburgh 1987},
 EDITOR={D.~H.~Pitt and A.~Poign{\'e} and D.~E.~Rydeheard},
 SERIES={Lecture Notes in Computer Science},
 PUBLISHER={Springer-Verlag, Berlin},
 VOLUME=283,
 YEAR=1987,
 PAGES={12--39}}