Tyr - D - Pen - Gly - Phe - L - Pen and Tyr - D - Pen - Gly - Phe - D - Pen are Selective Ligands for the "d" - Binding Site Alistair D Corbett, Maureen G C Gillan, Hans W Kosterlitz, Alexander T McKnight and Stewart J Paterson, 'Tyr - D - Pen - Gly - Phe - L - Pen and Tyr - D - Pen - Gly - Phe - D - Pen are Selective Ligands for the "d" - Binding Site' reprinted from 'British Journal of Pharmacology', 80 (1983), 669. 1983