Meyer, B. 1982. “Opiate Receptors and Opioid Peptides: "The Poppies of the Mind"”. Suid-Afrikaans Tydskrif Vir Natuurwetenskap En Tegnologie / <i>South African Journal of Science and Technology</I&gt; 1 (4), 195-98. https://doi.org/10.4102/satnt.v1i4.1164.