![](https://www.pdfsearch.io/img/c32e2856975d8f11e502b6cd940fa18f.jpg) Date: 2010-10-07 18:20:31
| | Vol 457 | 5 February 2009 | doi:nature07673 LETTERS Fossil steroids record the appearance of Demospongiae during the Cryogenian period Gordon D. Love1,2, Emmanuelle Grosjean3, Charlotte Stalvies4, David A. Fike5Add to Reading ListSource URL: earthsciences.ucr.eduDownload Document from Source Website File Size: 355,97 KBShare Document on Facebook
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