[1] Glivjak F., Kyš P., Plesník J.:
On the extension of graphs with a given diameter without superfluous edges. Mat. časop. 19 (1969), 92 - 101.
MR 0302503
[2] Glivjak F., Kyš P., Plesník J.:
On irreducible graphs with diameter two without triangles. Mat. časop. 19 (1969), 149-157.
MR 0302504