Vardanyan, Ruben; Vijay, Gokhale; Nichol, Gary S.; Liu, Lu; Kumarasinghe, Isuru; Davis, Peg; Vanderah, Todd; Porreca, Frank; Lai, Josephine; Hruby, Victor J. Bioorganic and Medicinal Chemistry, 2009 , vol. 17, # 14 p. 5044 - 5053