[2]Архивирано на сајту Wayback Machine (2. јул 2017) Connor, K. F. (2004): Update on oak seed quality research: Hardwood recalcitrant seeds. Proc. RMRS (USDA, Rocky Mountain Research Station): 111–116.
rngr.net
[1] Vozzo J. A., editor (2002): Tropical tree seed manual. Washington, DC: USDA Forest Service; Agriculture Handbook 721.
web.archive.org
[2]Архивирано на сајту Wayback Machine (2. јул 2017) Connor, K. F. (2004): Update on oak seed quality research: Hardwood recalcitrant seeds. Proc. RMRS (USDA, Rocky Mountain Research Station): 111–116.