And I found this on an MIT site (Sheesh! There's a lot out there analyzing this show!)
Another interesting case is Magnum, P.I. (CBS, 1980-1988): It is yet to be decided if the more characteristic features of the show, such as the flashback, and the voice-overs, evolved into a structural backbone before or after the printing of a ground-breaking article on the way this specific show dealt with collective memories of the Vietnam era (see Newcomb 1985). After Newcomb's definition of the cumulative narrative was coined producers would openly refer to that term and even claim in backsight that they used his analysis as sort of a manual for later seasons of the series.
Now where can we find the Newcomb article? Still searching . . .