Aziz, Ghazi M., and Sahar I. Hussien. “Determination of the Optimum Conditions for Gelatinase Production from Local Isolate Enterococcus Faecalis B91”. Journal of Biotechnology Research Center (JOBRC), vol. 5, no. 2, June 2011, pp. 75-84, doi:10.24126/jobrc.2011.5.2.168.