avar                    Asymptotic variance of Estimator
ids_with_multiple_obs   'ids_with_multiple_obs' returns a vector of
                        values that occur multiple times
nonredundant            Nonredundant
projdummies             Projection Dummies
projvar                 Project Variables
regress1                Regression
where_id_with_single_obs
                        'where_id_with_single_obs' returns a true/false
                        vector, Does this dummy occur multiple times?
xtreg2way               Estimation of Two Way Fixed Effects Model
