Vietnam era music- do you mean composed at the time of the Vietnam War, or popular at that time? Composed at that time would include all the parodies of songs from the Civil War to WW2 and Korean war, etc., as well as the tin pan alley and Nashville stuff, etc., a very large number, to emphasize what could have been left unsaid. The latter would be a very, very large number, to emphasize what could have been left unsaid.

So- specifically what?