Ekong, U. S., and E. C. Ibezim. “Antibiotic Production, Activity Spectra and Plasmid Analysis of Streptomyces Species Isolated from Soil”. Nigerian Journal of Pharmaceutical and Applied Science Research, vol. 4, no. 3, Aug. 2020, pp. 33-41, http://mail.nijophasr.net/index.php/nijophasr/article/view/93.