University of St. Andrews (UK)
University of St. Andrews: Georg Friedrich Bernhard Riemann
This University of St. Andrews site contains biographical information as well as accomplishments of Riemann.
Wolfram Research
Wolfram Math World: Complex Plane
This math site gives a visual representation of a complex plane with several values plotted, the site explains that any complex number can be plotted on such a plane. The site contains links to related words and topics.
Curated OER
University of St Andrews: Georg Friedrich Bernhard Riemann
This University of St. Andrews site contains biographical information as well as accomplishments of Riemann.