Não informado. (1969). Industrial and Commercial Training. J. Wellens, Industrial and Technical Training.
Chicago-Zitierstil (17. Ausg.)Não informado. Industrial and Commercial Training. Guilsborough, Inglaterra: J. Wellens, Industrial and Technical Training, 1969.
MLA-Zitierstil (8. Ausg.)Não informado. Industrial and Commercial Training. J. Wellens, Industrial and Technical Training, 1969.
Achtung: Diese Zitate sind unter Umständen nicht zu 100% korrekt.