フェルミオン・ダブリング
↑ H.B. Nielsen, M. Ninomiya (1981). “Absence of Neutrinos on a Lattice. 1. Proof by Homotopy Theory”. Nucl.Phys. B 185 (1): 20–40. doi:10.1016/0550-3213(81)90361-8.
↑ H.B. Nielsen, M. Ninomiya (1981). “Absence of Neutrinos on a Lattice. 2. Intuitive Topological Proof”. Nucl.Phys. B 193 (1): 173–194. doi:10.1016/0550-3213(81)90524-1.