APA

(2016). Keilhau- Froebel's Valley of Education. : Community Playthings.

Chicago

2016. Keilhau- Froebel's Valley of Education. : Community Playthings.

Harvard

(2016). Keilhau- Froebel's Valley of Education. : Community Playthings.

MLA

Keilhau- Froebel's Valley of Education. : Community Playthings. 2016.