Yagi, M., widad M. O. Modawei, and M. A. A. A. “Effect of Nitrogen and Spacing in Growth, Yield and Quality of Celocia Cristata”. International Journal of Sciences: Basic and Applied Research (IJSBAR), vol. 18, no. 1, Aug. 2014, pp. 132-4, https://gssrr.org/index.php/JournalOfBasicAndApplied/article/view/2704.