1 作者 Pakull, B., Groppe, K., Meyer, M., Markussen, T., Fladung, M., 年份 2009. 题目 Genetic linkage mapping in aspen (Populus tremula L. and Populus tremuloides Michx.). 期刊Tree Genet. Genomes 期,页数5, 505–515. 2 作者 Wolfe JA, 年份1987. 题目 An overview of the origins of the modern vegetation and flora of the northern Rocky Mountains. 期刊Annals of the Missouri Botanical Garden 期 页数74: 785-803. 3 作者Lo EYY, Stefanovi S, Christensen KI, Dickinson TA, 年份2009. 题目Evidence for genetic association between East Asian and western North American Crataegus L. (Rosaceae) and rapid divergence of the eastern North American lineages based on multiple DNA sequences. 期刊Molecular Phylogenetics and Evolution 期 页数51: 157e168.