\begin{publication} 

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
% use the form of bibliography but numbers are followed by a close round bracket (close parenthesis)
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

\item W. Tapanyo and P. Jaipong. ``Chromatic numbers of suborbital graphs for the modular group and the extended modular group.'' \textit{Journal of Mathematics}, vol. 2017, Article ID 7458318, 2017. doi:10.1155/2017/7458318

\item P. Jaipong and W. Tapanyo. ``Connectivity of suborbital graphs for the congruence subgroups of the extended modular group.'' \textit{Communications in Mathematics and Applications}, (accepted on March 15, 2017)

\item W. Tapanyo and P. Jaipong. ``Generalized classes of suborbital graphs for the congruence subgroups of the modular group.'' \textit{Algebra and Discrete Mathematics}, (submitted in October 2016)

\item W. Tapanyo and P. Jaipong. ``Maximal buttonings of certain graphs.'' \textit{Thai Journal of Mathematics}, (submitted in October 2016)

\item W. Tapanyo and P. Jaipong. ``Suborbital graphs for the congruence subgroup $ \Gamma_1(n) $ of the modular group.'' (in preparation)
\end{publication}