BERGANT, Klemen, et al. “Flowering Prediction of Pear Tree (Pyrus Communis L.), Apple Tree (Malus Domestica Borkh) and Plum Tree (Prunus Domestica L.) - Similarities and Differences”. Acta Agriculturae Slovenica, vol. 77, no. 1, May 2001, pp. 3–10, https://doi.org/10.14720/aas.2001.77.1.15673.