THE ADVENTURE GIRLS AT K BAR O -- 1936. A.L. Burt; Saalfield.
THE ADVENTURE GIRLS IN THE AIR -- 1936. A.L. Burt; Saalfield.
THE ADVENTURE GIRLS AT HAPPINESS HOUSE -- "The
Adventure Girls start college and are immediately involved in
investigating who is trying to kill the new dean." -- 1936. A.L. Burt; Saalfield.
THE ADVENTURE GIRLS ON VACATION -- announced at the end of #3
-- "Suppose we leave the Adventure Girls here, discussing their
plans for the summer. We shall join them again for more excitement in
The Adventure Girls on Vacation" -- but may be a "phantom
title," as I can't find it listed in WorldCat.