Zumstein, J., and U. Heininger. “Decline of Pertussis in Hospitalised Children Following the Introduction of Immunisation in Pregnancy – Results from a Nationwide, Prospective Surveillance Study, 2013–2020”. Swiss Medical Weekly, vol. 151, no. 4950, Dec. 2021, p. w30064, doi:10.4414/SMW.2021.w30064.