# M. Levy, Handbook of Elastic Properties of Solids, Liquids, and Gases (2001)
# C. Zambaldi, "Orientation informed nanoindentation of a-titanium: Indentation pileup in hexagonal metals deforming by prismatic slip", J. Mater. Res., Vol. 27, No. 1, Jan 14, 2012
# Better use values from L. Wang, Z. Zheng, H. Phukan, P. Kenesei, J.-S. Park, J. Lind, R.M. Suter, T.R. Bieler, Direct measurement of critical resolved shear stress of prismatic and basal slip in polycrystalline Ti using high energy X-ray diffraction microscopy, Acta Mater 2017