- http://en.wikipedia.org/wiki/Annelid
- http://www.ento.csiro.au/education/allies/annelida.html
- http://www.ento.csiro.au/education/allies/annelida.htm
- https://www.google.com/search?q=annelids&client=safari&rls=en&source=lnms&tbm=isch&sa=X&ei=8IKfU4-zNIWpyATzhYG4Cg&ved=0CAYQ_AUoAQ&biw=1222&bih=607
- http://wiki.hicksvilleschools.org/groups/hsbiology/wiki/b9456/Nervous_System_.html
- http://wiki.hicksvilleschools.org/groups/hsbiology/wiki/b9456/Nervous_System_.html
- http://facultyweb.brynmawrschool.org/UpperSchool/Science/Classes/AllBiology/bio/biotext/biowilson/2009-2010/HONORS/EOL%20Honors1/Euna%20Park/evolution.html
- http://annelidsg.blogspot.com/2007/03/respiration-system.html
- http://www.earthlife.net/inverts/annelida.html
- http://www.britannica.com/EBchecked/topic/26308/annelid