Hanh, N.V., Linh, N.V. and Nguyen, B.X. 2014. Cryopreservation of immature porcine oocytes by Cryotop. Academia Journal of Biology. 35, 4 (Mar. 2014), 516–521. DOI:https://doi.org/10.15625/0866-7160/v35n4.3784.