José de Andrade, Cristiano, et al. “Comparative Study: Bench-Scale Surfactin Production from Bacillus Subtilis Using Analytical Grade and Concentrated Glycerol from the Biodiesel Industry”.
International Journal of Scientific World, vol. 5, no. 1, Dec. 2016, pp. 28-37,
https://doi.org/10.14419/ijsw.v5i1.6965.