Hatzichristou D, Cuzin B, Martin-Morales A, Buvat J, Porst H, Laferriere N, Bandel TJ, Montorsi F; Vardenafil Study Group. Vardenafil improves satisfaction rates, depressive symptomatology, and self-confidence in a broad population of men with erectile dysfunction. J Sex Med. 2005 Jan;2(1):109–16. doi: 10.1111/j.1743-6109.2005.20111.x. PMID: 16422913.