[1] G. BIRKHOFF:
Lattice Theory. Am. Math. Soc. Colloquium Publications, vol. XXV, New York 1948.
MR 0029876 |
Zbl 0033.10103
[2] O. ORE:
Theory of Graphs. Am. Math. Soc. Colloquium Publications, vol. XXXVIII, Providence 1962.
MR 0150753 |
Zbl 0105.35401
[3] L. NEBESKÝ:
Algebraic Properties of Trees. AUC Philologica Monographia XXV, Universita Karlova, Praha 1969.
MR 0274210
[4] L. NEBESKÝ: Algebraické vlastnosti stromů. manuscript, 1969.