Lagrangian for Frenkel electron and position’s non-commutativity due to spin Alexei A. Deriglazov and Andrey M. Pupasov-Maksimov Eur. Phys. J. C, 74 10 (2014) 3101 Published online: 16 October 2014 DOI: 10.1140/epjc/s10052-014-3101-2