@article{montmollin_1999,  title={Analysis and models of operators activities in complex natural life environments},  volume={9},  ISSN={0103-6513},  url={https://doi.org/10.1590/S0103-65131999000400002},  DOI={10.1590/S0103-65131999000400002},  number={spe},  journal={Production},  publisher={Associação Brasileira de Engenharia de Produção},  author={Montmollin, Maurice de},  year={1999},  month={Dec},  pages={29–42} }