Alain Pirotte. A Precise Definition of Basic Relational Notions and of the Relational Algebra. SIGMOD Record, 13(1):30-45, 1982. [doi]
@article{Pirotte82,
title = {A Precise Definition of Basic Relational Notions and of the Relational Algebra},
author = {Alain Pirotte},
year = {1982},
doi = {10.1145/984514.984516},
url = {http://doi.acm.org/10.1145/984514.984516},
tags = {relational algebra, algebra},
researchr = {https://researchr.org/publication/Pirotte82},
cites = {0},
citedby = {0},
journal = {SIGMOD Record},
volume = {13},
number = {1},
pages = {30-45},
}