Não informado. Philips Research Reports. Philips Gloeilampenfabrieken, Research Laboratory.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रNão informado. Philips Research Reports. Eindhoven, Holanda: Philips Gloeilampenfabrieken, Research Laboratory.
एमएलए (8वां संस्करण) प्रशस्ति पत्रNão informado. Philips Research Reports. Philips Gloeilampenfabrieken, Research Laboratory.
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