1. Dixon, H. H., Ann. Botany (London) 8: 468 (1894).
2. Askenasy, E., Verhandl. Naturhist.-med. Ver. Heidelberg 5: 325 (1895).
3. Transpiration and the Ascent of Sap in Plants 1914
4. Renner, O., Jahrb. wiss. Botan. 56: 617 (1915).
5. Ursprung, A., Ber. deut. bot. Ges. 33: 153 (1915).