5Qnexel P, Pasquale G D I, Garfl G. Discovery of a new Zelkova in southeastern Sicily:Biogeograohical and historical significance[J]. Comptes rendus de 1' academie des sciences, 1993,3 (16):1.
6Wada K. The flora and vegetation of the interior of central Japan I. Big, old zelkova trees (Zelkova serrata) in Nagano Prefecture (Japan)[J]. Bulletin of the inatitute of Nature Education in Shiga Heights, 1991,10(28):29-32.
7Cho H J, Lee Y W, Lee D S, et al. Forest vegetation of Mt. Baek-Hwa (South Korea)z A phytosociological study[J]. Journal of Korean Forestry Society ,1991,80(1):42-53.
