R. Penrose (1971a), "Angular momentum: an approach to combinatorial spacetime," in T. Bastin (ed.), Quantum Theory and Beyond, Cambridge University Press (this paper can be found online on John C. Baez's website); and R. Penrose (1971b), "Applications of negative dimensional tensors," in D. J. A. Welsh (ed.), Combinatorial Mathematics and its Applications (Proc. Conf., Oxford, 1969), Academic Press, pp. 221–244, esp. p. 241 (the latter paper was presented in 1969 but published in 1971 according to Roger Penrose, "On the Origins of Twistor Theory"Archiviato il 23 giugno 2021 in Internet Archive. in: Gravitation and Geometry, a Volume in Honour of I. Robinson, Biblipolis, Naples 1987).
ucr.edu
math.ucr.edu
R. Penrose (1971a), "Angular momentum: an approach to combinatorial spacetime," in T. Bastin (ed.), Quantum Theory and Beyond, Cambridge University Press (this paper can be found online on John C. Baez's website); and R. Penrose (1971b), "Applications of negative dimensional tensors," in D. J. A. Welsh (ed.), Combinatorial Mathematics and its Applications (Proc. Conf., Oxford, 1969), Academic Press, pp. 221–244, esp. p. 241 (the latter paper was presented in 1969 but published in 1971 according to Roger Penrose, "On the Origins of Twistor Theory"Archiviato il 23 giugno 2021 in Internet Archive. in: Gravitation and Geometry, a Volume in Honour of I. Robinson, Biblipolis, Naples 1987).
web.archive.org
R. Penrose (1971a), "Angular momentum: an approach to combinatorial spacetime," in T. Bastin (ed.), Quantum Theory and Beyond, Cambridge University Press (this paper can be found online on John C. Baez's website); and R. Penrose (1971b), "Applications of negative dimensional tensors," in D. J. A. Welsh (ed.), Combinatorial Mathematics and its Applications (Proc. Conf., Oxford, 1969), Academic Press, pp. 221–244, esp. p. 241 (the latter paper was presented in 1969 but published in 1971 according to Roger Penrose, "On the Origins of Twistor Theory"Archiviato il 23 giugno 2021 in Internet Archive. in: Gravitation and Geometry, a Volume in Honour of I. Robinson, Biblipolis, Naples 1987).