Paper  bibtex   

@book{montessori_maria_2015,
	address = {Amsterdam},
	title = {Maria {Montessori} {Writes} to {Her} {Father}: {Letters} from {California}, 1915},
	url = {http://www.worldcat.org/oclc/927808426},
	language = {eng},
	publisher = {Montessori-Pierson Publishing Company},
	author = {Montessori, Maria},
	year = {2015}
}