Ismael , Bairam Solomon. 2013. “EFFECT OFCHEMICAL FERTILIZERS LEVELS (NPK) ON THE GROWTHAND FLOWERING OF TWO VARIETY OF TULIP ( Tulipa gesneriana). ”. Diyala Agricultural Sciences Journal 5 (2):312-18. https://journal.djas.uodiyala.edu.iq/index.php/dasj/article/view/2768.