Massa, A. F., J. Borges da Costa, P. Filipe, and M. S. Marques. “PYODERMA GANGRENOSUM ASSOCIATED WITH HIDRADENITIS SUPURATIVA – A RARE BUT WELL ESTABLISHED ASSOCIATION”. Journal of the Portuguese Society of Dermatology and Venereology, Vol. 72, no. 3, Oct. 2014, pp. 401-5, doi:10.29021/spdv.72.3.287.