Hartman, K. L.; Visser, F.; Hendriks, A. J.E. (14 March 2008). "Social structure of Risso's dolphins (Grampus griseus) at the Azores: a stratified community based on highly associated social units". Canadian Journal of Zoology86 (4): 294–306. doi:10.1139/Z07-138. பன்னாட்டுத் தர தொடர் எண்:0008-4301.
Hartman, K. L.; Visser, F.; Hendriks, A. J.E. (14 March 2008). "Social structure of Risso's dolphins (Grampus griseus) at the Azores: a stratified community based on highly associated social units". Canadian Journal of Zoology86 (4): 294–306. doi:10.1139/Z07-138. பன்னாட்டுத் தர தொடர் எண்:0008-4301.