Charm sea effects on charmonium decay constants and heavy meson masses - ALPHA Collaboration Salvatore Calì, Kevin Eckert, Jochen Heitger, Francesco Knechtli and Tomasz Korzec Eur. Phys. J. C, 81 8 (2021) 733 Published online: 14 August 2021 DOI: 10.1140/epjc/s10052-021-09520-y