A mapping-independent analysis for the spectra of the non-commutative two-dimensional harmonic oscillatorJian Jing, Jun-Ying Ma, Yong-Hong Guo and Jian-Feng ChenEur. Phys. J. C, 56 4 (2008) 591-595DOI: https://doi.org/10.1140/epjc/s10052-008-0682-7