In this study, the holidays are classified into four categories such as regular holidays,
festivals, upper Austrian holidays (except German holidays) and school vacations. The
regular holidays include the official nine holidays in Bavaria, Germany except Easter and
Christmas. The festivals include Easter and Christmas. Usually, the stores are closed during
regular holidays and festivals. The missing sales data during regular holidays and festivals are
filled with the estimated values from trend using linear interpolation, in order to maintain the
alignment of data between time periods, i.e., seasonality. The upper Austrian region has extra
three holidays than Bavarian regular holidays. The upper Austrian holidays are considered only
because of cross-border shopping. To evaluate the holiday effects, the effects are categorized
into before holidays, after holidays, Christmas (before and after), Easter (before and after),
before and on Upper Austrian holidays and school vacations. The holiday effects can be
incorporated into the model using dummy variables, i.e., ordinary days are coded as 0 and days
with
effects are coded as 1.