na YOGYA-02090000017461 20090227022748.0 eng 010-020900000017461 YOPDYOG (B) 621.316 621.316 Ryd E RYDER, R.W Earthing principles and practice R.W. Ryder Ed. 1 London Sir Isaac Pitman &Sons 1952 xi, 108 hlm ilus 22 cm Bibliografi : hlm. 105 Indeks Listrik, Tenaga YOPDYOG a000006340