@article{DBLP:journals/dm/NowakowskiW01,
author = {Richard J. Nowakowski and
C. A. Whitehead},
title = {Ordered graceful labellings of the 2-star},
journal = {Discrete Mathematics},
volume = {233},
number = {1-3},
year = {2001},
pages = {183-191},
ee = {http://dx.doi.org/10.1016/S0012-365X(00)00237-5},
bibsource = {DBLP, http://dblp.uni-trier.de}
}