@article{morgado_willey_2003,  title={Effects of plant population and nitrogen fertilizer on yield and efficiency of maize-bean intercropping},  volume={38},  ISSN={0100-204X},  url={https://doi.org/10.1590/S0100-204X2003001100002},  DOI={10.1590/S0100-204X2003001100002},  number={11},  journal={Pesquisa Agropecuária Brasileira},  publisher={Embrapa Secretaria de Pesquisa e Desenvolvimento; Pesquisa Agropecuária Brasileira},  author={Morgado, Luiz Balbino and Willey, Robert William},  year={2003},  month={Nov},  pages={1257–1264} }