S. A. . Shlahi and Z. N. H. . Al- Hattab, “Effect of N-methyl-N-nitro-N-nitrosoguanidine (NTG) on callus induction and survival rate on mature embryos of beans (Phaseolus vulgaris)”, JOBRC, vol. 3, no. 2, pp. 91–98, Jun. 2009.