15th UK and European Meeting on the Foundations of Physics. Leeds, UK. Retrieved 2008-06-21. ↑ F. A. M. Frescura, B. J. Hiley: Algebras, quantum theory and pre-space, published in Revista Brasileira de Fisica, Volume Especial, Julho 1984, Os 70 anos de Mario Schonberg, pp. 49–86, p. 2 ↑ Jørgen Kalckar, Niels Bohr, Léon Rosenfeld, Erik Rüdinger, Finn Aaserud (1996).