Filho, Francisco Rodrigues Freire, et al. “Adaptability and Stability of Grain Yield in Climbing and Brown Coat Cowpea Genotypes”. Pesquisa Agropecuaria Brasileira, vol. 38, no. 5, May 2003, pp. 591-8, doi:10.1590/S1678-3921.pab2003.v38.6612.