By David W. Ferriday
Originally published in The Vexilloid Tabloid #31, December 2011
- United Nation News Centre: As world passes 7 billion milestone, UN urges action to meet key challenges. October 31, 2011.
- Seven Billion. National Geographic‘s year-long series on population
- Human Population Reaches 7 Billion–How Did This Happen and Can It Go On? By David Biello, Scientific American, October 28, 2011.
- www.worldof7billion.org – Educational materials from Population Connection (formerly ZPG)