Zaffaroni, E., Silva, M. A. V. and de Azevedo, P. V. (1994) “Agroclimatic potential of sunflower in Paraiba State, Brazil. I. Temperature and solar radiatio”, Pesquisa Agropecuaria Brasileira, 29(10), pp. 1483–1491. doi: 10.1590/S1678-3921.pab1994.v29.4199.