Exton M, Bondert A, Kruger T, et al. Cardiovascular and endocrine alterations after masturbation-induced orgasm in women. Psychosom Med 1999;61:280-289. DOI: 10.1097/00006842-199905000-00005

Fuss, Johannes; Bindila, Laura; Wiedemann, Klaus; Auer, Matthias K.; Briken, Peer; Biedermann, Sarah V. (2017). Masturbation to Orgasm Stimulates the Release of the Endocannabinoid 2-Arachidonoylglycerol in Humans. The Journal of Sexual Medicine, 14(11), 1372–1379. doi:10.1016/j.jsxm.2017.09.016

LoPiccolo J, Lobitz WC. 1972.  The role of masturbation in the treatment of orgasmic dysfunction. Arch Sex Behav.  Dec;2(2):163-71. doi: 10.1007/BF01541865.PMID: 4680816.