Al-roomia, AssRana A.H. “The Effect of Gamma Radiation on Callus Growth and Plantlet Regeneration of Four Tomato Hybrid Lycopersicon Esculentum Mill In Vitro”. Journal of Biotechnology Research Center, vol. 3, no. 1, Jan. 2009, pp. 56-62, doi:10.24126/jobrc.2009.3.1.46.