1. Boyd W. C. 1966. Fundamentals of immunology 4th ed. p. 717-722. Interscience New York.
2. Cochran W. G. and G. M. Cox. 1967. Experimental designs 2nd ed. Wiley New York.
3. Cox D. R. 1958. Planning of experiments. Wiley New York and London.
4. Fisher R. A. 1925. Statistical methods for research workers. Oliver and Boyd Edinburgh.
5. Fisher R. A. 1935. The design of experiments. Oliver and Boyd Edinburgh.