@article{WilkeMohrTenfordeetal.2021,
  author    = {Jan Wilke and Lisa Mohr and Adam S. Tenforde and Pascal Edouard and Chiara Fossati and Marcela Gonz{\´a}lez-Gross and Celso S{\´a}nchez Ram{\´i}rez and Fernando Lai{\~n}o and Benedict Tan and Julian David Pillay and Fabio Pigozzi and David Jimenez-Pavon and Bernhard Novak and Johannes Jaunig and Mandy Zhang and Mireille van Poppel and Christoph Heidt and Steffen Willwacher and Gustavo Yuki and Daniel E. Lieberman and Lutz Vogt and Evert Verhagen and Luiz Hespanhol and Karsten Peter Hollander},
  title     = {A pandemic within the pandemic? Physical activity levels substantially decreased in countries affected by COVID-19},
  journal   = {International journal of environmental research and public health},
  volume    = {2021},
  number    = {5, art. 2235},
  pages     = {1 -- 11},
  doi       = {10.3390/ijerph18052235},
  year      = {2021},
}