R. el-Hak

Serum levels of procaine in human after peri-oral injections.

M. Gadalla, R. el-Hak, 1985, Die Pharmazie.

Failure of inferior alveolar nerve block.

R. el-Hak, 1971, Egyptian dental journal.

The history of anesthesia.

R. el-Hak, 1970, Egyptian dental journal.