Pavol Hell, Jaroslav Nesetril. Images of Rigid Digraphs. Eur. J. Comb., 12(1):33-42, 1991. [doi]
@article{HellN91,
title = {Images of Rigid Digraphs},
author = {Pavol Hell and Jaroslav Nesetril},
year = {1991},
doi = {10.1016/S0195-6698(13)80005-4},
url = {http://dx.doi.org/10.1016/S0195-6698(13)80005-4},
researchr = {https://researchr.org/publication/HellN91},
cites = {0},
citedby = {0},
journal = {Eur. J. Comb.},
volume = {12},
number = {1},
pages = {33-42},
}