Opiliones: Harvestmen
- The characteristics of these spiders, their life cycle, feeding and habitat, with illustrations.
- http://www.ento.csiro.au/education/allies/opiliones.html

Opiliones in Belgium
- Species list and distribution maps for Belgian harvestmen.
- http://www.elve.net/opilio

Opiliones
- Brief article on harvestmen from South Africa's Biodiversity Explorer.
- http://www.museums.org.za/bio/arachnids/opiliones.htm