Посилання:On a group theoretical construction of expanding graphs / V.A. Ustimenko // Algebra and Discrete Mathematics. — 2003. — Vol. 2, № 3. — С. 102–109. — Бібліогр.: 15 назв. — англ.
Підтримка:The author is deeply grateful to A. V. Borovik for useful remarks and
support of this research. I am indebted to the referee for a careful reading
and his help to improve style and prepare this note for a wider audience.