Originally Posted by Dr. Drib
Longyear, Barry B.. "Misencounter." Alien Encounters. Edited by Jan Finder.
McCaffrey, Anne. Decision at Doona. Del Rey, 1969.
McCaffrey, Anne. The Rowan. Ace, 1991.
McCaffrey, Anne and Jody Lynn Nye. Treaty at Doona. Ace, 1994.
Have to Add a couple more to McCaffrey's List.
Her Nimisha's Ship Does deal with a First Contact situation, as do her Acorna series.