For the next few years to follow he worked on this subject with his post-doctoral student , Paul Newbold ; .
They wrote a book which became a standard reference in time series forecasting ( published in 1977 ) .
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 ) .