1.  www.stanford.edu/group/Urchin/nathistory.htm
2.  www.cyber-nurse.com/quiz/urchin.htm
3.  http://school.discovery.com
4.www.pac.dfo-mpo.gc.ca/ops/fm/shellfish/sea-urchin/biology_urchin.htm
5.  Gotshall, D.W.  1994.  Guide To Marine Ivertebrates Alaska to Baja California, Sea Challenges Publications.  pg.81.
6.  Reish, D.J.  1972.  Marine Life of Southern California Emphasizing Marine Life of Los Angeles-Orange Counties, Kendall/Hunt Publishing Company.
7.  www.state.ak.us/adfg/geninfo/press/1996/12-26-96.htm
8.  www.foodsubs.com/caviar.htm
9.  www.digitalsushi.net
10. www.saintbrendan.com