Hole pairing and ground state properties of high-Tc superconductivity within the t–t′–J–V model Krishanu Roy, Papiya Pal, Subhadip Nath and Nanda Kumar Ghosh Eur. Phys. J. B, 91 4 (2018) 64 Published online: 06 April 2018 DOI: 10.1140/epjb/e2018-80488-y