Always use et al. after the first author's family name.
Norheim et al. (2001) did not find a reduction in nausea symptoms.
Claims that acupuncture could substantially reduce nausea symptoms were not supported (Norheim et al., 2001).
Norheim, A. J., Pederson, E. J., Fønnebø, V., & Berge, L. (2001). Acupressure treatment of morning sickness in pregnancy: A randomized, double-blind, placebo-controlled study. Scandinavian Journal of Primary Health Care, 19(1), 43-47. https://doi.org/10.1080/02813430120819