1. Bergmann, R., Ludbrook, J., Spooren, W.P.J.M.: Different outcomes of the Wilcoxon–Mann–Whitney test from different statistics packages. Am. Stat. 54, 72–77 (2000)
2. Berry, K.J., Martin, T.W., Olson, K.F.: A note on fourfold point correlation. Educ. Psychol. Meas. 34, 53–56 (1974)
3. Blalock, H.M.: A double standard in measuring degree of association. Am. Sociol. Rev. 28, 988–989 (1963)
4. Blalock, H.M.: Social Statistics, 2nd edn. McGraw–Hill, New York (1979)
5. Bonett, D.G., Price, R.M.: Inferential methods for the tetrachoric correlation coefficient. Psych. Rep. 30, 213–225 (2005)