1Herta. Blaukopt, ed. Gustav Mahler Briefe : 1879-1911. Publication of the International Gustav Mahler Society, Vienna/Hamburg. 1982. 347.
2Martner, Kunt :Selected lettles of Gustav Mahler, The original edition by Alma Mahler,enlarge and edited by Kunt Martner. Faber and Faber, 1979, London . 139.