| Description | Raymond J Vavrek, Ren - Lin Cui, Eunice J York, John M Stewart, Stewart J Paterson and Hans W Kosterlitz, 'Lysine Substitution Increases Mu - Selectivity of Potent Di - and Tri - Peptide Enkephalin Analogs' reprinted from 'Life Sciences', 33 (1983), 451 - 454. |