Circle packings and co-compact extensions of Kleinian groups. R. Brooks — 1986 Inventiones mathematicae
Compactness and finiteness theorems for isospectral manifolds. R. Brooks; P. Petersen; P. Perry — 1992 Journal für die reine und angewandte Mathematik
On Cheeger's inequality. R. Brooks; P. Perry; Petersen V; P. — 1993 Commentarii mathematici Helvetici