Focchi, Sandro Souza, et al. “Arbuscular Mycorrhizal Fungi in Citrus Cultivation under Conventional and Organic Management”. Pesquisa Agropecuaria Brasileira, vol. 39, no. 5, May 2004, pp. 469-76, doi:10.1590/S1678-3921.pab2004.v39.6795.