H. Neudecker, Bounds for the Bias of the LS Estimator of σ 2 in the Case of a First-Order (Positive) Autoregressive Process when the Regression Contains a Constant Term, Econometrica, Vol. 46, No. 5 (Sep., 1978), pp. 1223-1226

[This paper considers the least squares estimator of @? extasciicircum2 in the linear model with disturbances generated by a first-order autoregressive process. It is well known that the estimator is biased. In this paper an attempt is made to establish bounds for the bias. These bounds depend on n, k, and @r, where n is the number of observations, k is the number of parameters, and @r is the (positive) coefficient of the autoregressive process.]

H. Neudecker, Bounds for the Bias of the Least Squares Estimator of @s^2 in the Case of a First-Order Autoregressive Process (Positive Autocorrelation), Econometrica, Vol. 45, No. 8 (Nov., 1977), p. 2006