@article{10_37236_12725,
     author = {Bo  Ning and Mingqing Zhai},
     title = {Counting substructures and eigenvalues. {II:} {Quadrilaterals}},
     journal = {The electronic journal of combinatorics},
     year = {2025},
     volume = {32},
     number = {4},
     doi = {10.37236/12725},
     zbl = {8120087},
     url = {http://geodesic.mathdoc.fr/articles/10.37236/12725/}
}