Nippon Telegraph & Telephon Public Corporation. (1981). Guide to NTT. Tokyo: Nippon Telegraph & Telephon Public Corporation.
シカゴスタイル引用形Nippon Telegraph & Telephon Public Corporation. Guide to NTT. Tokyo: Nippon Telegraph & Telephon Public Corporation, 1981.
MLA引用形式Nippon Telegraph & Telephon Public Corporation. Guide to NTT. Tokyo: Nippon Telegraph & Telephon Public Corporation, 1981.
警告: この引用は必ずしも正確ではありません.