TY  - RPRT
TI  - Extended relational operators for statistical data manipulations in medical databases.
AU  - H H Yao
AU  - T S Yamashita
PY  - 1989
DO  - 10.1016/0010-4809(89)90072-4
UR  - https://pubmed.ncbi.nlm.nih.gov/2591206/
ID  - 2591206
ER  -