1. Afifi, A. A., and Elashoff, R. M. (1967), “Missing observations in multivariate statistics II: point estimation in simple linear regression,” Journal of the American Statistical Association, 62, 595–604.
2. Anderson, A. B., Basilevsky, A., and Hum, D. P. J. (1983), “Missing data: a review of the literature,” in P.H. Rossi, J. D. Wright, and A. B. Anderson (eds.), Handbook of Survey Research, pp. 415–494, New York: Academic Press.
3. Anderson, T. W. (1957), “Maximum likelihood estimation for the multivariate normal distribution when some observations are missing,” Journal of the American Statistical Association, 52, 200–203.
4. Azen, S. P., Van Guilder, M., and Hill, M. A. (1989), “Estimation of parameters and missing values under a regression model with non-normally distributed and non-randomly incomplete data,” Statistics in Medicine, 8, 217–228.
5. Baker, S. G., and Laird, N. M. (1988), “Regression analysis for categorical variables with outcome subject to nonignorable nonresponse,” Journal of the American Statistical Association, 81, 29–41.