Não informado. Philips Research Reports. Philips Gloeilampenfabrieken, Research Laboratory.
Chicago-viite (17. p.)Não informado. Philips Research Reports. Eindhoven, Holanda: Philips Gloeilampenfabrieken, Research Laboratory.
MLA-viite (8. p.)Não informado. Philips Research Reports. Philips Gloeilampenfabrieken, Research Laboratory.
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