No Inv.: 2931-2934/P/Perp/92/4c~172/U/Perp/93/1c
No Inv.: 4205-4209/P/Perp/95/5c
No Inv.: 331/PS2PT Dikti/Perp/95/1c
No Inv.: 1293-1296/P/Perp/92/4c~3145-3146/P/Perp/91/2c
No Inv.: 706-707/P/Perp/92/2c
No Inv.: 2246-2250/P/Perp/95/5c~2320-2324/P/Perp/95/5c
No Inv.: 440/S/Perp/95/1c
No Inv.: 1688/S/Perp/91/1c
Judul asli :"The Essence of information systems"