Phanikumar CV, Maitra B. Modeling willingness-to-pay values for rural bus attributes under different trip purposes. JTRF. 2006;45(2):31-44. doi: 10.22004/ag.econ.206787
Arana JI, Jarén C, Arana A, Arazuri S. Pruebas diagnósticas en la clasificación de productos agrícolas. Horticultura. 2001;19:20-6.
Williams VSL, Wakeford ME. The predictive validity of the National Teacher Examinations for performance in teacher education programs. Educ Psychol Meas. 1993;53(2):533-9. doi: 10.1177/0013164493053002023