For the next few years to follow he worked on this subject with his post-doctoral student, Paul Newbold; and they wrote a book which became a standard reference in time series forecasting (published in 1977).
Nos seguintes anos traballou no tema co estudante de posgrao, Paul Newbold; e xuntos publicaron en 1977 un libro que se converteu na referencia estándar de predicións en series temporais..