- Sanders, R When Thor Heyerdahl was delighted to be wrong: The Case of the Guara or Centerboard, published in Fall 2003 issue of 21st Century Science & Technology, retrieved on Jan 24, 2015
- Stein, Stephen K. (2017-04-24). The Sea in World History: Exploration, Travel, and Trade [2 volumes]. ABC-CLIO. p. 214. ISBN 9781440835513.
- Abstracts of New World Archaeology. University of Utah Press. 1961. p. 168.
Inca seamen could tack and beat to windward through the use of wooden centerboards (guaras) set between cracks in the log rafts.