Arif, T., and S. S. Amin. “Palmoplantar Keratoderma Progradiens Et Transgradiens Associated With Periodontitis – A Case of Papillon-Lefevre Syndrome”. Journal of Pakistan Association of Dermatologists, vol. 26, no. 2, Nov. 2016, pp. 166-70, doi:10.66344/jpad.26.2.2016.64.