References
- Hempel , C. G. 1965 . “ ‘The theoretician's dilemma’ ” . In Aspects of Scientific Explanation , 186 New York : Free Press .
- Coombes , C. H. 1964 . A Theory of Data , 3 – 57 . New York : Wiley .
- Bush , R. R. , Abelson , R. P. and Hyman , R. 1956 . Mathematics for Psychologists: Examples and Problems , New York : Social Science Research Council .