Sadia Tabassum, Mumtaz Ali Qureshi, Maria Kazi, Haji Khan Khoharo, Salman Ahmad Farsi Kazi, Naveed Kazi. “Vitamin D3 & Serum Calcium Levels in Premenstrual Syndrome”. Journal of Peoples University of Medical &Amp; Health Sciences Nawabshah. (JPUMHS), vol. 4, no. 2, June 2014, pp. 105-9, http://publication.pumhs.edu.pk/index.php/ojs/article/view/141.