Não informado. (2004). Steam and Heating Engineer. Troup Publications.
Chicago-referens (17:e uppl.)Não informado. Steam and Heating Engineer. London: Troup Publications, 2004.
MLA-referens (8:e uppl.)Não informado. Steam and Heating Engineer. Troup Publications, 2004.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.