Zetkina Alena I. «On equations in free groups with commutant restrictions on solutions» // Prikladnaya Diskretnaya Matematika - Applied Discrete Mathematics 2024. №66 C.5-13
Genze L.V. «Free n-periodic topological groups» // 2010. №3(11) C.23-28
Roman’kov V.A. «Superpositions of free Fox derivations» // Applied Discrete Mathematics 2022. №56 C.28-32