Que, S. K. T., Fraga-Braghiroli, N., Grant-Kels, J. M., Rabinovitz, H. S., Oliviero, M., & Scope, A. (2016). 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, 1-2. https://doi.org/10.5826/dpc.0603a01