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	...	References: - Influence of NiCl2on the Skeleton Formation in Sea Urchin: Armstrong et al. (1993) Development 119:833-840; Hardin et al. (1992) Development 116:671-685. - Fertilization And Early Development Of The Sea Urchin. Cebra-Thomas, Judy. Spring 1998. - Basics of Sea Urchin Development. Cebra-Thomas, Judy. Spring 1999. Gilbert SF. editor. 1997. Developmental biology. 5th ed.: Sinauer Associates, Inc., Sunderland, Mass, 918 p.