England and Wales. Sovereign (1625-1649 : Charles I).
International Labour Office
Paul Hadlock
United States. Bureau of Labor Statistics.
Elliott Jaques
Bruce Montgomery
Linda Hardy
James Roberson
National Industrial Conference Board.
Henry Hamilton
International Labour Organisation. Metal Trades Committee. Session
Carol E. Morgan
Vernon H. Jensen
Barbara Drake
Paolo Spriano
Günter Ahrer
Great Britain. Ministry of Labour. Manpower Research Unit.
Friedrich Hermann Hegi
Candace Leslie