@article{oai:repo.qst.go.jp:00082034,
 author = {Toru, Sakai and Toru, Sakai},
 journal = {Applied Magnetic Resonance},
 month = {Oct},
 note = {The direct electron paramagnetic resonance (EPR) absorption between the singlet ground state and the triplet excited states of spin gap systems is investigated. Such an absorption, which is forbidden by the conservation of the total spin quantum number in isotropic Hamiltonians, is allowed by some anisotropies; the staggered g-tensor and the Dzyaloshinskii-Moriya interaction. Selection rules in the presence of these interactions were presented in our previous works. We review the selection rules of the EPR transition of the spin gap with some numerical demonstrations and discuss some applications.},
 pages = {507--521},
 title = {EPR Theories for Selection Rules to Observe the Spin Gap},
 volume = {52},
 year = {2020}
}