It's interesting to see no other than Harry Sinden pushing for that series as early as 1969. But then, it was reoccuring topic that kept popping up and was commented on by a variety of people in the late 1960s, so it's not a surprise. For example, in Richard J. Bendell's book 1972 – The Summit Series, broadcaster Dick Irvin Jr. is quoted as saying during the 1970 NHL All-Star Game: "When you see a power play out there with the likes of Davey Keon, Bobby Orr, Bobby Hull and Gordie Howe I'm sure a lot of people in Canada have it going through their minds: what would these fellows do against the Russians?"