Babijchuk, V. G., and A. V. Kozlov. 2008. “Effect of Extreme Cooling on Indices of Vegetative Regulation of Cardiac Rhythm in Rats of Different Age Groups”. Problems of Cryobiology and Cryomedicine 18 (3):374-78. https://journal.cryo.org.ua/index.php/probl-cryobiol-cryomed/article/view/415.