ProQuest. (2004). ProQuest Science Journals. USA: Umi company.
Trích dẫn kiểu ChicagoProQuest. ProQuest Science Journals. USA: Umi company, 2004.
MLA CitationProQuest. ProQuest Science Journals. USA: Umi company, 2004.
Advarsel: Disse citationer er muligvist ikke 100% nøjagtige.