The 1971 model saw a drastic redesign to its predecessors.
The GR01 recorded poor results; the model never saw the finish line.
Roy's model sees the an individual as a set of interrelated systems (biological, psychological and social).
We can make models to use, but we cannot test the models to see how well they work.
Many models of PS/2 systems saw a production life span that took them well into the late 1990s.
The 1937 models saw the return of coupes and convertibles to the Ambassador lines.
We change the model to reflect it, and see what difference it makes to the results.
On the contrary, 1977 models saw a wide array of changes.
This model sees two important improvements to the series.
This model also saw improvements in the exhaust system, a smaller tank and 8kg weight reduction.