Philip Wadler. Theorems for Free!. In FPCA. pages 347-359, 1989. [doi]
@inproceedings{Wadler89,
title = {Theorems for Free!},
author = {Philip Wadler},
year = {1989},
doi = {10.1145/99370.99404},
url = {http://doi.acm.org/10.1145/99370.99404},
researchr = {https://researchr.org/publication/Wadler89},
cites = {0},
citedby = {0},
pages = {347-359},
booktitle = {FPCA},
}