Philips. (1981). PTI in brief. Nertherlands: Philips' Telecommunicatie Industrie BV.
Trích dẫn kiểu ChicagoPhilips. PTI in Brief. Nertherlands: Philips' Telecommunicatie Industrie BV, 1981.
ציטוט MLAPhilips. PTI in Brief. Nertherlands: Philips' Telecommunicatie Industrie BV, 1981.
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