1. J. D. van der Waals: Die Continuität des gasförmigen und flüssigen Zustandes. Leipzig 1899.
2. G. Teichner: Untersuchungen über kritische Dichte. Ann. Phys., Lpz. Bd. 13 (1904) S. 595/610.
3. J. S. Tapp, W. W. R. Steacie u.O. Maass: Density discontinuities at the critical temperature. Canad. J. Res. Bd. 9 (1933) S. 613/29.
4. O. Maass u.A. L. Geddes: The persistence of the liquid state of aggregation above the critical temperature. The system ethylene. Phil. Trans. roy. Soc. A Bd. 236 (1937) S. 303/32.
5. S. G. Mason, S. N. Naldrett u.O. Maass: A study of the coexistence of the liquid and gaseous states of aggregation in the critical temperature region. Ethane. Canad. J. Res. Bd. 18 (1940) S. 103/17.