References

Lester B. Peason College. "Phascolosoma agassizii". Racerocks. 7 December 2002. taxalab/bio2002/phascolosomaa.htm>.

Miller, Kenneth R. and Joseph Levine. Biology. 4th ed. Upper Sadle River, NJ: Prentice Hall, 1998.

Pearse, Viki., and others. Living Invertebrates. Boston, Massachusetts:Blackwell Scientific Publications, 1987.

Rice, Mary E. "Possible Boring Structures of Sipunculids". Integrative and Comparative Biology. 1969. icb.oxfordjournals.org/cgi/content/abstract/9/3/803>

Ruppert, Edward, E., Richard S. Fox and Robert D. Barnes. Invertebrate Zoology: A functional evolutionary approach.
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