1. Allen, E. H.: 1976, Negative probabilities and the uses of signed probability theory, Philosophy of Science 43, 53–70.
2. Araki, G.: 1948, Theory of elliptically polarized photons, Physical Review 74, 472–479.
3. Birkhoff, G. and Von Neumann, J.: 1936, The logic of quantum mechanics, Annals of Mathematics 37(2nd Series), 823–843.
4. Feynman, R.: 1987, Negative probabilities, in B. J. Hiley and F. D. Peat (eds.), Quantum Implications, Routledge, New York.
5. Foulis, D.: 1999, A half-century of quantum logic: What have we learned? in D. Aerts and J. Pykacz (eds.), Quantum Structures and the Nature of Reality, Kluwer, Dordrecht.