Ann Q. Gates, Vladik Kreinovich. Why is a function defined as set of ordered pairs?. ACM SIGCSE Bulletin, 29(4):57, 1997. [doi]
@article{GatesK97,
title = {Why is a function defined as set of ordered pairs?},
author = {Ann Q. Gates and Vladik Kreinovich},
year = {1997},
doi = {10.1145/271125.271156},
url = {http://doi.acm.org/10.1145/271125.271156},
researchr = {https://researchr.org/publication/GatesK97},
cites = {0},
citedby = {0},
journal = {ACM SIGCSE Bulletin},
volume = {29},
number = {4},
pages = {57},
}