マリア・クラウス・ベルテ
Maria Kraus-Boelté and John Kraus, The Kindergarten Guide (1882), republished by Kindergarten Messenger (January, 2001) Full text online
Article in The kindergarten and its relation to elementary education (Chicago 1907)
Characteristics of Froebel's Method, Kindergarten Training in Foster Wygant, Art in American Schools in the Nineteenth Century (Cincinnati 1983) - facsimile of NEA Proceedings (1879)