Kaiser H, Cornelissen G, Halberg F 1990: "Palaeochronobiology circadian rhythms, gauges of adaptive Darwinian evolution: about 7-day circaseptan rhythms, gauges of integrative evolution".
In 1990, Kaiser, Cornelissen, and Halberg explored the use of circadian rhythms as measures of adaptive evolutionary change in organisms, particularly highlighting the significance of 7-day circaseptan rhythms.