Wolfram Research
Wolfram Math World: Cissoid
This site explains what a cissoid is in mathematics and its literal meaning in the english language. The site then names seven different Cissoids and the two curves and pole which create each of these named Cissoids.
Wolfram Research
Wolfram Math World: Cissoid of Diocles Pedal Curve
Short site explaining the Cissoid of Diocles Pedal Curve. The site has links to related topics, and includes a graph and a brief explanation.
University of St. Andrews (UK)
University of St. Andrews: Cissoid of Diocles
This site, which is provided for by the University of St. Andrews, describes the properties behind cissoids and graphs them.