Kawakami, Saito, Takahashi. Overexpression of p2lWaf1/Cip1immunohistochemical staining in Bowen's disease, but not in disseminated superficial porokeratosis. British Journal of Dermatology. 1999 Oct;141(4):647–51. doi: 10.1046/j.1365-2133.1999.03102.x.