1
by Apel, Willi
Published 1947
Harvard University Press

2
by Daniel, Ralph T., Apel, Willi
Published 1960
Harvard University Press

3
by Apel, Willi, Davison, Archibald T.
Published 1949
Harvard University Press

4
by Apel, Willi, Davison, Archibald T.
Published 1950
Harvard University Press