%0 Journal Article
%A et The EHT Collaboration al.
%B ApJL
%D 2019
%G eng
%P 6
%T First M87 Event Horizon Telescope Results. VI. The Shadow and Mass of the Central Black Hole
%U https://iopscience.iop.org/article/10.3847/2041-8213/ab1141
%V 875