Diameters, distortion, and eigenvalues. - Rostislav I. Grigorchuk; Piotr W. Nowak (Eur. J. Comb., 2012)

Certifying numerical estimates of spectral gaps. - Marek Kaluba; Piotr W. Nowak (Groups Complex. Cryptol., 2018)

Spectral Gap for the Cohomological Laplacian of SL 3 (ℤ). - Marek Kaluba; Piotr Mizerka; Piotr W. Nowak (Exp. Math., 2025)