1. Trait-names, a psycho-lexical study;Allport;Psychological Monographs,1936
2. The use of API career factors as Holland occupational types;Ahadi;Educational and Psychological Measurement
3. The vocational interests of Dartmouth College freshmen: 1947-67;Campbell;The Personnel and Guidance Journal,1969
4. A merger in vocational interest research: Applying Holland's theory to Strong's data;Campbell;Journal of Vocational Behavior,1972