Ashraf, A., H. Khan, and N. Iqbal. “CORRELATION OF NASOLABIAL ANGLE WITH MAXILLARY INCISOR INCLINATION AND UPPER LIP THICKNESS”. Pakistan Oral & Dental Journal, Vol. 38, no. 3, Nov. 2018, pp. 317-9, https://podj.com.pk/index.php/podj/article/view/261.