http://www.ugr.es/~lstocino/placida_cremoniana.htm
http://www.medslugs.de/E/Med/Placida_cremoniana.htmPlacida_cremoniana/Selection.htm
http://www.nembro.info/uk_placida_cremoniana.html
http://hypselodoris.blogspot.pt/2010/02/placida-cremoniana-trinchese-1893.html
http://opistobranquis.info/en/guia/sacoglossa/placida-cremoniana/
http://www.medslugs.de/E/Atl-E/Placida_cremoniana.htmPlacida_cremoniana/Selection.htm