Definition of gravitational local spatial densities for spin-0 and spin-1/2 systems J. Yu. Panteleeva, E. Epelbaum, J. Gegelia and U. -G. Meißner Eur. Phys. J. C, 83 7 (2023) 617 Published online: 14 July 2023 DOI: 10.1140/epjc/s10052-023-11746-x