Cristian M. Conde Ezequiel Dratman Luciano N. Grippo On the spectral radius of unbalanced signed bipartite graphs. 114942 2026 349 Discret. Math. 5 https://doi.org/10.1016/j.disc.2025.114942 db/journals/dm/dm349.html#CondeDG26 streams/journals/dm