New topological structures of Skyrme theory: baryon number and monopole number Y. M. Cho, Kyoungtae Kimm, J. H. Yoon and Pengming Zhang Eur. Phys. J. C, 77 2 (2017) 88 Published online: 09 February 2017 DOI: 10.1140/epjc/s10052-017-4655-6