HOF, M., R. I. DAHLKE, T. DANDEKAR, M. KALTDORF, and L. A. BECK. “A Non-Invasive Manual Method for the Assessment of Pregnancy in Female Scyliorhinus Canicula Catsharks”. Mediterranean Marine Science, vol. 19, no. 1, May 2018, pp. 201-8, doi:10.12681/mms.13838.