Halmi, M. I. E.; Shukor, M. S.; Masdor, N. A.; Shamaan, N. A.; Shukor, M. Y. Testing the Normality of Residuals on Regression Model for the Growth of Sludge Microbes on PEG 600. J Environ Microbiol Toxicol 2015, 3, 14-17.