TSVETKOV, I., C. BENELLI, and M. CAPUANA. “Application of Vitrification-Derived Cryotechniques for Long-Term Storage of Poplar and Aspen (Populus spp.) Germplasm”. Agricultural and Food Science, vol. 18, no. 2, Jan. 2009, pp. 160-6, doi:10.2137/145960609789267515.