de Souza, Adilson Pacheco, et al. “Basal Temperature and Thermal Sum in Phenological Phases of Nectarine and Peach Cultivars”. Pesquisa Agropecuaria Brasileira, vol. 46, no. 12, Feb. 2012, pp. 1588-96, doi:10.1590/S1678-3921.pab2011.v46.11279.