Two characterizations of the grid graphs. - Brhane Gebremichel; Mengyue Cao; Jack H. Koolen (Discret. Math., 2021)

There Does Not Exist a Strongly Regular Graph with Parameters $(1911, 270, 105, 27)$. - Jack H. Koolen; Brhane Gebremichel (Electron. J. Comb., 2022)

Distance-regular graphs with a few q-distance eigenvalues. - Mamoon Abdullah; Brhane Gebremichel; Sakander Hayat; Jack H. Koolen (Discret. Math., 2024)

Non-existence of two infinite families of strongly regular graphs. - Jack H. Koolen; Brhane Gebremichel; Jeong Rye Park; Jongyook Park (Eur. J. Comb., 2025)