1. J.S. Islinger, K. Gutfruend, R.G. Maguire, and O.H. Olson, "Mechanism of Reinforcement of Fiber-Reinforced Structural Plastics and Composites," WADC Tech. Report 59-600, Part I, March, 1960 , p. 24.
2. J.G. Vail, Soluble Silicates, Vol. I, Reinhold (1952), p. 171.