@article{202109.0302,
	doi = {10.20944/preprints202109.0302.v2},
	url = {https://doi.org/10.20944/preprints202109.0302.v2},
	year = 2021,
	month = {December},
	publisher = {Preprints},
	author = {Yin Zhu},
	title = {Gravitational Field and Mass},
	journal = {Preprints}
}