Andrew, D. P. S., Pederson, P. M., & McEvoy, C. D. (2011). Research methods and design in sport management. Champiagn, IL: Human Kinetics.
Luiselli, J. K., & Reed, D. D. (2011). Social validity. In Encyclopedia of Child Behavior and Development. (Vol. 3, p. 1406). New York, NY: Springer US.
Messick, S. (1989). Validity. In R. L. Linn (Ed.), Educational measurement 3rd ed., pp. 13-104). New York: Macmillan.
Pogrund, R. L., Darst, S., & Munro, M. (2015). Initial validation study for a scale used to determine service intensity for itinerant teachers of students with visual impairments. Journal of Visual Impairment & Blindness,109(6), 433-444
United States Department of Education. (2004). Regulations: Part 300.320. In Building the legacy: IDEA 2004 (Child with a disability). Retrieved from http://idea.ed.gov/explore/view/p/%2Croot%2Cregs%2C300%2CD%2C300%252E320%2C