The extensibility of local Lie groups of transformations and groups on surfaces. Mostow, G. D. Annals of mathematics, 1950.
bibtex   
@article{mostow_extensibility_1950,
	title = {The extensibility of local {Lie} groups of transformations and groups on surfaces},
	journal = {Annals of mathematics},
	author = {Mostow, George Daniel},
	year = {1950},
	pages = {606--636},
}

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