[1] P. ERDÖS, A. RÉNYI: Asymmetric graphs. Acta Math. Acad. Sci. Hungar. 14 (1963), 295-315. MR 0156334

[2] F. HARARY, G. PRINS: The number of homeomorphically irreducible trees and other species. Acta Math. 101 (1959), 141-162. MR 0101846 | Zbl 0084.19304

[3] J. NEŠETŘIL: Structure of asymmetric graphs. Thesis 1969, McMaster University, Hamilton, Ontario.

[4] L. V. QUJNTAS: Extrema concerning asymmetric graphs. Journ. of Comb. Th. 3, 1 (1967), 57-82. MR 0211905

[5] G. SABIDUSSI: Existence and structure of self - adjoint graphs. Math. Zeitschr. 104 (1968), 257-280. MR 0227044 | Zbl 0157.31003