BibTex format
@article{Graefe:2008:25/255206,
author = {Graefe, EM and Guenther, U and Korsch, HJ and Niederle, AE},
doi = {25/255206},
journal = {JOURNAL OF PHYSICS A-MATHEMATICAL AND THEORETICAL},
title = {A non-Hermitian PT symmetric Bose-Hubbard model:: eigenvalue rings from unfolding higher-order exceptional points},
url = {http://dx.doi.org/10.1088/1751-8113/41/25/255206},
volume = {41},
year = {2008}
}