Paper  bibtex   

@article{kilpatrick_montessori_1913-2,
	title = {The {Montessori} {Method}},
	volume = {20},
	copyright = {Public Domain},
	url = {https://catalog.hathitrust.org/Record/100340465},
	language = {eng},
	journal = {Proceedings of the Annual Convention of the International Kindergarten Union},
	author = {Kilpatrick, William H.},
	month = may,
	year = {1913},
	pages = {122--127}
}