Part I: Ann. Éc. 41, 1-25 (1924); Part II: ibid. Penrose, Roger (1971). “Functions of unfavourable dimensional tensors”. Combinatorial Arithmetic and its Functions. Penrose, Roger (1971). “Angular momentum: an method to combinatorial area-time”. In Bastin, Ted (ed.). Quantum Principle and Beyond. Penrose, Roger (1987). “On the Origins of Twistor Principle”. In Rindler, Wolfgang; Trautman, Andrzej (eds.). Gravitation and Geometry, a Volume in Honour of Ivor Robinson. Amitabha Sen, “Gravity as a spin system,” Phys. Abhay Ashtekar, “New variables for classical and quantum gravity,” Phys. Abhay Ashtekar, “New Hamiltonian formulation of basic relativity,” Phys. Wilson, Ok. (1974). “Confinement of quarks”. Bodily