Não informado. (1971). NLL Announcement Bulletin. National Lending Library for Science and Technology.
Chicago-viite (17. p.)Não informado. NLL Announcement Bulletin. Boston, Inglaterra: National Lending Library for Science and Technology, 1971.
MLA-viite (8. p.)Não informado. NLL Announcement Bulletin. National Lending Library for Science and Technology, 1971.
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