TY - JOUR A1 - et D. Psaltis al. AU - BT - Physical Review Letters IS - 14 LA - eng PY - 2020 EP - 141104 T1 - Gravitational Test beyond the First Post-Newtonian Order with the Shadow of the M87 Black Hole T2 - Physical Review Letters TI - Gravitational Test beyond the First Post-Newtonian Order with the Shadow of the M87 Black Hole UR - https://ui.adsabs.harvard.edu/abs/2020PhRvL.125n1104P/abstract VL - 125 Y1 - 2020 ER -