Que, Syril Keena T., Naiara Fraga-Braghiroli, Jane M. Grant-Kels, Harold S. Rabinovitz, Margaret Oliviero, and Alon Scope. “A Pink Papule on the Back of an 82-Year-Old Man: An Example of the Buttonhole Sign on Reflectance Confocal Microscopy”. Dermatology Practical & Conceptual (July 31, 2016): 1–2. Accessed April 25, 2026. https://www.dpcj.org/index.php/dpc/article/view/dermatol-pract-concept-articleid-dp0603a01.