"Steve Ballmer talks about the current state of Microsoft, his Twitter investment, and how sports tech can help the Clippers". Interview with Matt Rosoff, www.businessinsider.com. February 6, 2016.
Hillary Clinton's speech at the Clinton-Sanders Democratic presidential debate in Durham, New Hampshire, hosted by MSNBC, www.nytimes.com. February 4, 2016.
"A Note on the Theory of the Black Market" by Kenneth E. Boulding in "The Canadian Journal of Economics and Political Science", Volume 13, No. 1 (pp. 115-118), www.jstor.org. February 1947.