Heavy neutrino mixing in the T2HK, the T2HKK and an extension of the T2HK with a detector at Oki IslandsYugo Abe, Yusuke Asano, Naoyuki Haba and Toshifumi YamadaEur. Phys. J. C, 77 12 (2017) 851DOI: https://doi.org/10.1140/epjc/s10052-017-5294-7