P. Suwan-vajokkasikij, D. Rerkrai, P. Tunktongharaotai, M. Dakeing, and S. Pongsamran, “Socio-economic Background Receiving Favorite Agricultural Radio Broadcasting Program of the Receivers in Central Provinces and Its Impact”, kasetsart J. Soc. Sci., vol. 7, no. 1, pp. 48–54, Jan. 1986.