Effect of low-temperature storage of placenta on its extract properties - O. A. Nardid; E. D. Rozanova; L. V. Tsymbal; S. V. Repina; E. I. Naumenko; D. N. Pogozhikh; N. T. Markova; I. P. Vysekantsev (Problems of cryobiology and cryomedicine, 2008)