Minimum size of a graph or digraph of given radius
Inform. Process. Lett. 109 (2009), 971--973.
BibTex references
@Article\{DV09,
author = "Dankelmann, Peter and Volkmann, Lutz",
title = "Minimum size of a graph or digraph of given radius",
journal = "Inform. Process. Lett.",
volume = "109",
pages = "971--973",
year = "2009",
}