Petyim, Somsin, Roungsin Choavaratana, Somboon Kunathikom, Pitak Laokirkkiat, and Japarath Prechapanich. 2007. “Freezing Effect on Post-Thawed Sperm Characteristics Especially Sperm DNA Integrity Comparing Between Liquid Nitrogen Vapour and Computerized Program Freezer”. Siriraj Medical Journal 59 (6):298-302. https://he02.tci-thaijo.org/index.php/sirirajmedj/article/view/246163.