Energy levels and their degeneracies for two-ring Ising chains of spins-
with NN and NNN couplings: spin frustration of ferromagnetic and antiferromagnetic orders
and
Eur. Phys. J. Plus, 136 8 (2021) 884
Published online: 27 August 2021
DOI: 10.1140/epjp/s13360-021-01863-5