Santi, D., Granata, A. R. M., Guidi, A., Pignatti, E., Trenti, T., Roli, L., Bozic, R., Zaza, S., Pacchioni, C., Romano, S., Nofer, J. R., Rochira, V., Carani, C., & Simoni, M. (2016). six months of daily treatment with vardenafil improves parameters of endothelial inflammation and of hypogonadism in male patients with type 2 diabetes and erectile dysfunction: a randomized, double-blind, prospective trial. European journal of endocrinology, 174(4), 513–522. http://access.bl.uk/ark:/81055/vdc_100035034955.0x000023