@inproceedings{m1978matrix,
  title={Matrix canonical realizations of the Lie algebra o (m, n). II. Casimir operators},
  author={M Havlek, and Pavel Exner},
  url={http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20191020134419481343768},
  booktitle={Czechoslovak Journal of Physics B},
  volume={28},
  number={9},
  pages={949-962},
  year={1978},
}
             
            
                
M Havlek, and Pavel Exner. Matrix canonical realizations of the Lie algebra o (m, n). II. Casimir operators. 1978. Vol. 28. In Czechoslovak Journal of Physics B. pp.949-962. http://archive.ymsc.tsinghua.edu.cn/pacm_paperurl/20191020134419481343768.