@article{BeckerSperlichZinneretal.2020,
  author    = {Manuel Becker and Billy Sperlich and Christoph Zinner and Silvia Achtzehn},
  title     = {Intra-Individual and Seasonal Variation of Selected Biomarkers for Internal Load Monitoring in U-19 Soccer Players},
  journal   = {Frontiers in Physiology},
  volume    = {11},
  number    = {838},
  doi       = {10.3389/fphys.2020.00838},
  year      = {2020},
}