Soares, J.B. et al. 2003. Sperm tail flexibility test: a simple test for selecting viable spermatozoa for intracytoplasmic sperm injection from semen samples without motile spermatozoa . Revista do Hospital das Clínicas. 58, 5 (Jan. 2003), 250–253. DOI:https://doi.org/10.1590/S0041-87812003000500003.