@article{hackney_machado_2012,  title={Hormonal status, creatine kinase and soccer: a need for research},  volume={56},  ISSN={0004-2730},  url={https://doi.org/10.1590/S0004-27302012000900014},  DOI={10.1590/S0004-27302012000900014},  number={9},  journal={Arquivos Brasileiros de Endocrinologia & Metabologia},  publisher={Sociedade Brasileira de Endocrinologia e Metabologia},  author={Hackney, Anthony C. and Machado, Marco},  year={2012},  month={Dec},  pages={683–685} }