Iqbal, M., A. Shahzad, and I. Ahmed. “Allelic Variation at the Vrn-A1, Vrn-B1, Vrn-D1, Vrn-B3 and Ppd-D1a Loci of Pakistani Spring Wheat Cultivars”. Electronic Journal of Biotechnology, vol. 14, no. 1, Jan. 2011, https://www.ejbiotechnology.info/index.php/ejbiotechnology/article/view/v14n1-6.