Peng ea 2007
Peng X., Knapp B.I., Bidlack J.M., Neumeyer J.L. Pharmacological properties of bivalent ligands containing butorphan linked to nalbuphine, naltrexone, and naloxone at mu, delta, and kappa opioid receptors. //J. Med. Chem. 2007. Vol. 3. * 50 (9). P. 2254-2