National Geographic used OSU associate professor of history Dr. Tonia Sharlach as a primary source for its article on unusual taxes in ancient civilizations.  

Sharlach comments on taxes which predated coin and paper money, noting taxes were paid by everything from brooms to kegs of beer.  

An expert on ancient history, Sumerian and Babylonian civilization and religion, Sharlach received her Ph.D. from Harvard in 1999 and published her dissertation on Babylonian taxes in 2004.  

National Geographic's article: http://news.nationalgeographic.com/2016/04/160414-history-bad-taxes-tax-day/