http://en.wikipedia.org/wiki/Uncertainty_and_errors_in_cfd_simulation
http://www.ece.rochester.edu/courses/ECE111/error_uncertainty.pdf
http://www.nhn.ou.edu/~johnson/Education/Juniorlab/Error-SigFig/SigFigin...
https://www.physics.upenn.edu/uglabs/lab_manual/Error_Analysis.pdf