Kollár, Alicia J., Mattias Fitzpatrick, Peter Sarnak, and Andrew A. Houck. 2019. “Line-Graph Lattices: Euclidean and Non-Euclidean Flat Bands, and Implementations in Circuit Quantum Electrodynamics”. Communications in Mathematical Physics 376: 1909-56. doi:10.1007/s00220-019-03645-8.