1. N-4 substituted 1(2-aryl-rthyl)4-piperidenyl-N-phenylproanamides, a novel series of extremely potent analgesics with unusually high safety margin;Van Bever;Arzneimittelforsch,1973
2. Sufentanil, a very potent and extremely safe intravenous morphine-like compound in mice, rats and dogs;Niemegeers;Drug Res,1976
3. A review of the chemical features associated with strong morphine-like activity;Janssen;Br J Anaesth,1962
4. Opiate receptors in the brain;Snyder;N Engl J Med,1977
5. Chemistry of narcotics and narcotic antagonists;Foldes,1954