Lutfi, D. A., S. Sumarji, and A. Daroni. “ The Influence of Socio-Economic Factors on The Productivity of Farmers in The Business of Layers in Blitar Regency”. ANIMAL PRODUCTION, Vol. 22, no. 1, Sept. 2020, pp. 44-54, doi:10.20884/1.jap.2020.22.1.17.