Reference:

If you wish to cite the Sponge Genetree Server, please use the following reference:

Erpenbeck D, Voigt O, Gültas M, Wörheide G. (2008): The Sponge Genetree Server - providing a phylogenetic backbone for poriferan evolutionary studies. Zootaxa 1939:58-60

Available from Zootaxa (with suscription) or directly from the SGS-authors.