HIEN, Bui Thi Thuy.
Functional dependencies with context dependent Null values in relational databases.
VNU Journal of Science: Natural Sciences and Technology, [S.l.], v. 15, n. 5, dec. 1999.
ISSN 2588-1140.
Available at: <https://js.vnu.edu.vn/NST/article/view/3769>. Date accessed: 22 nov. 2024.