1. Schwarttz L. Théorie des distributions, Paris (1950 - 1951). A more elementary treatment is given in Halperin, I., Introduction to the theory of distributions, Toronto. 1952.
2. Schönberg M. Quantum kinematics and geometry Avogadro Congress 1956; published in II Nuovo Cimento, supplement to the vol. 6. 1957;356.
3. Schönberg M. Quantum mechanics and geometry, São Paulo. 1957.
4. Schönberg M. Quantum mechanics and geometry I, II, III, IV and V, An. Acad. Brasil. Ci., 29, 473 and 30, 1, 117, 259 and 429. 1957;58.
5. Wiener N. Differential space. J Math P. Massachussets Institute of Technology. 1923.