Não informado. (1968). Modern data products, systems, services. Modern Data Services.
Παραπομπή σε μορφή Chicago (17η εκδ.)Não informado. Modern Data Products, Systems, Services. Framingham, Mass: Modern Data Services, 1968.
Παραπομπή σε μορφή MLA (8th εκδ.)Não informado. Modern Data Products, Systems, Services. Modern Data Services, 1968.
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