Fritz Feigl ; translated by Ralph E. Oesper. Translated by Ralph E. Oesper. by Fritz Feigl ; tr. by Ralph E. Oesper. by Fritz Feigl; tr. by Ralph E. Oesper. Hermann Hesse ; translated by Hilda Rosner. Fritz Deumlich ; [translated by Wolfgang Faig]. Rolf-Dieter Mu?ller ; translated by Janice W. Ancker. J. L. Lions, translated by Dr. S. K. Mitter. Dietrich Braess ; translated by Larry L. Shumaker. edited and translated by Frederick C. Beiser.