1. (2000). Missing data. Thousand Oaks, CA: Sage.
2. & (1983). Applied multiple regression/correlation analysis for the behavioral sciences (2nd ed.) Hillsdale, NJ: Erlbaum.
3. Missing Data in Likert Ratings: A Comparison of Replacement Methods
4. (Ed.). (1983). An overview of hot-deck procedures. New York: Academic Press.