Godfraind, T., & Ghyselburton, J. (1979). Cardioactive Properties of Sc4453, a Digoxin Analog With a Beta-pyridazine-c-17 Ring. European Journal of Pharmacology, 60(4), 337-344. https://doi.org/10.1016/0014-2999(79)90238-3 (Original work published 1979)