Raju Kocharekar. Nulls in Relational Databases: Revisited. SIGMOD Record, 18(1):68-73, 1989. [doi]
@article{Kocharekar89, title = {Nulls in Relational Databases: Revisited}, author = {Raju Kocharekar}, year = {1989}, doi = {10.1145/382272.382416}, url = {http://doi.acm.org/10.1145/382272.382416}, tags = {relational database}, researchr = {https://researchr.org/publication/Kocharekar89}, cites = {0}, citedby = {0}, journal = {SIGMOD Record}, volume = {18}, number = {1}, pages = {68-73}, }