MUKHOPADHYAY, GOUTAM, and JASMINA KHANAM. 2010. “Separation of Less Satisfactory Surface Active Antibiotic (Penicillin G) From Dilute Solution Using Foam Separation Method”. Asian Journal of Chemistry 21 (5):3861-68. https://asianpubs.org/index.php/ajchem/article/view/17364.