Cretaceous Sponges - Documentation and systematic description of fossil Cretaceous sponges (porifera) from the Campanian of Misburg and Höver, Germany. - http://www.cretaceous.de
Sponge Reefs on the Continental Shelf - Canadian Geological Survey program to study hexactinellid reefs. - http://www.pgc.nrcan.gc.ca/marine/9901_home.htm