Petyim, S.; Choavaratana, R.; Kunathikom, S.; Laokirkkiat, P.; Prechapanich, J. Freezing Effect on Post-Thawed Sperm Characteristics Especially Sperm DNA Integrity Comparing between Liquid Nitrogen Vapour and Computerized Program Freezer. Siriraj Med J 2007, 59, 298-302.