Babijchuk, L. A., V. V. Ryazantsev, P. M. Zubov, and O. L. Timchenko. “New Methods for Human Cord Blood Cryopreservation under Protection of Non-Penetrating Cryoprotectant PEO-1500”. Problems of Cryobiology and Cryomedicine, vol. 15, no. 3, Sept. 2005, pp. 556-60, https://cryo.org.ua/journal/index.php/probl-cryobiol-cryomed/article/view/1194.