@article{thulin_sjögren_2001,  title={Mechanical versus biological aortic valve implants in the elderly. A comparison of early and mid-term results},  volume={77},  ISSN={0066-782X},  url={https://doi.org/10.1590/S0066-782X2001001100001},  DOI={10.1590/S0066-782X2001001100001},  number={5},  journal={Arquivos Brasileiros de Cardiologia},  publisher={Sociedade Brasileira de Cardiologia - SBC},  author={Thulin, Lars I. and Sjögren, Johan L.},  year={2001},  month={Nov},  pages={395–398} }