A list of differencing lags can be placed in parentheses after the variable name to request that the series be differenced at these lags. For example, VAR=X (1) takes the first differences of X. VAR=X ...

One way of handling nonstationarity in time series is to compute first differences and fit a model to the differenced series unless the differenced series also looks nonstationary. In that case, ...

This work in Un-Differenced (UD) Integer Ambiguity Resolution (IAR) simplifies satellite navigation data processing and dramatically improves precise positioning accuracy.