Firoozbakht, Maryam, Akbarzadeh Kolahi, Saeed, Labeiki, Ghazal, Attar, Hossein. “Optimization of suitable nitrogen sources for the production of erythromycin by Saccharopolyspora erythraea.” Journal of Microbial World, vol. 8, no. 24, 2015, pp. 221-230.