COVID-19(4) G12(2) E00(1) declined(1) coronavirus(1) O23(1) COVID-19 testing(1) Stochastic structures(1) Critical case(1) time-varying(1) country(1) robust(1) Terrorist incident(1) Bewley transformation(1) functional(1) QARDL model(1) AI(1) Innovation spillover(1) COVID-19 pandemic(1) Moving windows(1) death(1) Frequency domain causality(1) parameter(1) Robust least square estimator(1) H56(1) reported(1) ARDL model(1) Food sales(1) negatively affected(1) O33(1)