**Paired t Test : **
Armitage P. Statistical Methods in Medical Research (1971). Blackwell Scientific Publications. Oxford. P.189-207

**Wilcoxon Paired Signed Rank Test : **

Siegel S and Castellan Jr. NJ (2000) Nonparametric Statistics for the
Behavioral Sciences. Second Edition. McGraw Hill, Sydney. ISBN0-07-100326-6 p. 95

**Permutation Test : **
Siegel S and Castellan Jr. NJ (2000) Nonparametric Statistics for the Behavioral
Sciences. Second Edition. McGraw Hill, Sydney. ISBN0-07-100326-6 p. 95-101