Note on the Sample Size to Achieve Normality for Estimators for the Gamma Distribution
L. R. Shenton, K.O. Bowman · Monthly Weather Review · 1973
The two-parameter gamma distribution is determined by its shape parameter γ and scale parameter, β. Maximum likelihood estimators of these γ̂/γ, β̂/β are distributed independent of β and tend to be normally distributed as the sample size n increases. Values of n are given (for selected values of γ) to ensure near normality.