graph; tree; Hamiltonian path; open Hamiltonian walk; diameter of graph
If $G$ is a graph, an open Hamiltonian walk is any open sequence of edges of minimal length which includes every vertex of $G$. In this paper bounds of lengths of open Hamiltonian walks are studied.
 Bermond J.C.: On Hamiltonian walks
. Proc. 5th British combinatorial conf. (1975), 41-51. MR 0398891
 Goodman S.E. and Hedetniemi S.T.: On Hamiltonian walks in graphs
. SIAM J. Comput 3 (1974), 214-221. MR 0432492
 Jolivet J.L.: Hamiltonian pseudocycles in graphs
. Proc. 5th Conf. Combinatorics, graph theory and computing (1975), Boca Raton, 529-533. MR 0364009