References
- Campbell , D. T. and Fiske , D. W. 1959 . Convergent and discriminant validity by the multitrait-multimethod matrix . Psychol. Bull. , 56 : 81 – 105 .
- Weiscerber , C. A. 1951 . Conscious perseveration and the persistence of autonomic activity as measured by recovery from the psychogalvanic response . J. Gen. Psychol. , 45 : 83 – 93 .