3S G Clark,G C Althouse. B-mode ultrasonographic examination of the accessory sex glands of boars. Theriogenology 2002,57:2003- 2013.
4Cemil Yagci, Sadettin Kupeli,Cisel Tok,et al. Efficacy of trans rectal ultrasonography in the evaluation of hematospermia. Journal of Clinical Imaging,2004,28:286-290.