@article{duthie_campbell_1991, title={Effects of plant debris on intensity of leaf spot diseases, incidence of pathogens, and growth of alfalfa}, volume={81}, DOI={10.1094/Phyto-81-511}, number={5}, journal={Phytopathology}, author={Duthie, J. A. and Campbell, C. L.}, year={1991}, pages={511} }
 @article{duthie_campbell_nelson_1991, title={Efficiency of multistage sampling for estimation of intensity of leaf spot disease of alfalfa in field experiments}, volume={81}, DOI={10.1094/Phyto-81-959}, number={9}, journal={Phytopathology}, author={Duthie, J. A. and Campbell, C. L. and Nelson, L. A.}, year={1991}, pages={959} }