University of British Columbia
University of British Columbia: Heron's Criterion
This site from the University of British Columbia describes and provides examples of Heron's Formula.
University of St. Andrews (UK)
University of St. Andrews: Biography of Hero
This University of St. Andrews site contains information on the life of Heron as well as his accomplishments.
Curated OER
University of St Andrews: Heron of Alexandria
This University of St. Andrews site contains information on the life of Heron as well as his accomplishments.