Siddiqui, S., Z. Wahid, and H. Talat. “Frequency and Clinical Patterns of Psoriatic Arthritis in Patients of Psoriasis”. Journal of Pakistan Association of Dermatologists, vol. 26, no. 4, Apr. 2017, pp. 328-31, http://www.jpad.com.pk/index.php/jpad/article/view/951.