Editor: Ralph K. Nair
American Council on Industrial Arts Teacher Education, 1959
Buku Teks SO
Colombo Plan Staff College for Technician education , 1986
Buku Teks
Matthias Pilz
VS Verlag, 2012
eBooks
Faitun Mariya
Fakultas Ekonomi dan Bisnis Universitas Indonesia, 2016
UI - Skripsi Membership
edited, S.G. Shapovalenko
Unesco, 1963
Buku Teks SO