David L. Shang. Covariant Specification. SIGPLAN Notices, 29(12):58-65, 1994.
@article{Shang94:0,
title = {Covariant Specification},
author = {David L. Shang},
year = {1994},
researchr = {https://researchr.org/publication/Shang94%3A0},
cites = {0},
citedby = {0},
journal = {SIGPLAN Notices},
volume = {29},
number = {12},
pages = {58-65},
}