Zárate, Néstor Antonio Heredia, et al. “Yield of Bunching Onion in Mono-Cropping System and Intercropped With Roquette With and Without Soil Covering With Chicken Manure”. Semina: Ciências Agrárias, vol. 27, no. 4, July 2006, pp. 505-14, doi:10.5433/1679-0359.2006v27n4p505.