"Richard Di Natale elected unopposed as new Greens leader after Christine Milne resigns - as it happened" by Daniel Hurst, www.theguardian.com. May 6, 2015.
"The Wisdom of Crowds: Why the Many Are Smarter Than the Few and How Collective Wisdom Shapes Business, Economies, Societies and Nations". Book by James Surowiecki, 2004.