Geospatial model of organophosphate insecticide residues in shallot land in Wanasari Sub-district, Brebes Regency, Central Java Province, IndonesiaIndratin, Mochamad Arief Budihardjo and Muhammad HelmiE3S Web Conf., 202 (2020) 06010DOI: https://doi.org/10.1051/e3sconf/202020206010