Golden rule series / 
Leavell, Ullin Whitney.
Friebele, Mary Louise.
Cushman, Tracie.
Caughran, Alex M.
New York, 
[1956-1959]
1. Paths to follow. [1956.] 2. Frontiers to explore. [1956.] 3. Widening horizons. [1956.] Open windows. By U.W. Leavell and M.L. Friebele. [1957.] Open doors. By U.W. Leavell and M.L. Friebele. [1957.] Open roads. By U.W. Leavell and M.L. Friebele. [1957.] Reading with purpose. By U.W. Leavell and A.M. Caughran. [1959.]
One volume is entered separately under title and under series.