@article {1444447,
	title = {First M87 Event Horizon Telescope Results. III. Data Processing and Calibration},
	journal = {The Astrophysical Journal Letters},
	volume = {875},
	year = {2019},
	pages = {3},
	url = {https://iopscience.iop.org/article/10.3847/2041-8213/ab0c57},
	author = {The EHT Collaboration et al.}
}
