David Roche, Debora Gil, & Jesus Giraldo. (2013).<a href='http://dx.doi.org/10.1016/j.drudis.2012.12.004''> "Multiple active receptor conformation, agonist efficacy and maximum effect of the system: the conformation-based operational model of agonism, "</a> . Drug Discovery Today, 18(7-8), 365–371.