references.txt

References
* Brown, MB. (1977) Algorithm AS 116: the tetrachoric correlation and its standard error. <em>Applied Statistics, 26</em>, 343-351.
* Drasgow F. (2006). Polychoric and polyserial correlations. In Kotz L, Johnson NL (Eds.), Encyclopedia of statistical sciences. Vol. 7 (pp. 69-74). New York: Wiley.
* Olsson, U. (1979) Maximum likelihood estimation of the polychoric correlation coefficient. Psychometrika 44, 443-460.
* Uebersax, J.S. (2006). The tetrachoric and polychoric correlation coefficients. Statistical Methods for Rater Agreement web site. 2006. Available at: http://john-uebersax.com/stat/tetra.htm . Accessed February, 11, 2010