“…In the stable case, i.e., lal < 1, with Sa(T)= [T/(1-a2)] 1/2, ~ is standard normal (Anderson (1959(Anderson ( , 1971). In the unstable case, i.e., lal --1, with Sa(T) = 2Ta, ~is the distribution of (W 2-1)/(f01W2ds) where {Ws;0<s< 1} is astandard Brownian motion (Rao (1966(Rao ( , 1978). Finally, in the explosive case, i.e., lal > 1, with Sa(T) = lalr(a 2 -1) -1, ~2~is Cauchy (White (1958(White ( , 1959 and Rio (1961Rio ( , 1966).…”