Dirac and non-Dirac conditions in the two-potential theory of magnetic charge John Scott, Timothy J. Evans, Douglas Singleton, Vladimir Dzhunushaliev and Vladimir Folomeev Eur. Phys. J. C, 78 5 (2018) 382 Published online: 17 May 2018 DOI: 10.1140/epjc/s10052-018-5867-0