1. Geir Agnarsson, Magnus M.Halldórsson: Coloring Powers of Planar Graphs. ACM Symposium on Discrete Algorithms (SODA) (2000).
2. M.I. Andreou, D.A. Fotakis, S.E. Nikoletseas, V.G. Papadopoulou and P.G. Spirakis: On Radiocoloring Hierarchically Specified Planar Graphs:
% MathType!MTEF!2!1!+-
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% hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr
% 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9
% vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x
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$$
\mathcal{P}\mathcal{S}\mathcal{P}\mathcal{A}\mathcal{C}\mathcal{E}
$$
-completeness and Approximations (full version). CTI Technichal Report 2002, URL
http://students.ceid.upatras.gr/~viki
.
3. B. S. Baker: Approximation algorithms for NP-complete problems on planar graphs. Journal of the ACM 41:153–180, 1994.
4. Bodlaender, H.L.: Planar graphs with bounded treewidth. TR RUU-CS-88-14, Department of Computer Science, University of Utrecht, The Netherlands, March, 1988.
5. Lect Notes Comput Sci;H.L. Bodlaender,2000