c_sja - critical values for Johansen maximum eigenvalue statistic
c_sjt - critical values for Johansen trace statistic
cadf - ADF statistic for residuals from a cointegrating regression
johansen - Johansen cointegration tests
kpss - KPSS unit root test
phil_perr - Phillips-Perron unit-root test
rztcrit - critical values for the cadf Zt statistic
schmiphi - computes Schmidt-Phillips test
schmiphi_tab - critical values for the Schmidt-Phillips statistic
ztcrit - critical values for the ADF Zt statistic