Set of functions to perform various bootstrap unit root tests for both individual time series
(including augmented Dickey-Fuller test and union tests), multiple time series and panel data; see
Palm, Smeekes and Urbain (2008) ,
Palm, Smeekes and Urbain (2011) ,
Moon and Perron (2012) ,
Smeekes and Taylor (2012) and
Smeekes (2015) for key references.