1. American Society for Testing Materials, " A.S.T.M. Standards on Textile Materials," Philadelphia , Oct. 1952, p. 536.
2. Chamot, E.M., and Mason, C.W. "Handbook of Chemical Microscopy," Vol. I, New York, John Wiley & Sons , 1938, p. 101.
3. Double Refraction Measurement of Fibers
4. Laboratory Techniques