Spring, Joel
American education / Joel Spring
McGraw-Hill, 2004
 Buku Teks
Slee, Carry
Joel
FMB, 2011
 Buku Teks
Spring, Joel
American education
McGraw-Hill, 2008
 Buku Teks
Hubbard, L. Ron, 1911-1986
Humanitarian education, literacy &​ civilization
Bridge Publications, Inc., 2012
 Buku Referensi
Anderson, Walter Truett
The upstart spring : Esalen and the American awakening / Walter Truett Anderson
Addison-Wesley, 1983
 Buku Teks SO