Bibliografi : hlm. 248-249
Judul asli : "Practical Problem in Soil Mechanics and Foundation Engineering"
No Inv.: 126351-126355/P/Perp/10/5c
No Inv.: 123171-123175/P/Perp/10/5c
No Inv.: 123196-123200/P/Perp/10/5c
No Inv.: 129075/S/Perp/10/1c
Judul asli : "Office Manajemen"
No Inv.: 138929/P/Perp/14/1c
No Inv.: 111075-111077/P/Perp/07/3c~119487-119489/P/Perp/09/3c~143763-143767/P/Perp/14/5c