Estimators of mean and standard deviation for censored normal samples which are based on linear systematic statistics and which use simple coefficients are almost as efficient as estimators using the best possible coefficients. Estimators are given for samples of size $N \leqq 20$ for censoring at one extreme and for several types of censoring at both extremes.
"Simplified Estimation from Censored Normal Samples." Ann. Math. Statist. 31 (2) 385 - 391, June, 1960. https://doi.org/10.1214/aoms/1177705900