South, David W.
Encyclopedic dictionary of gears and gearing
McGraw-Hill , 1995
 Buku Referensi
Carey, Samuel Warren
The expanding earth
Elsevier, 1976
 Buku Teks
Rakhit, A.K.
Heat treatment of gears: a practical guide for engineers
ASM International, 2000
 eBooks
Dudley, Darle W., editor
Gear handbook: the design, manufacture, and application of gears
McGraw-Hill, 1962
 Buku Referensi
Newman, Margaret A.
Health as expanding conciousness
C.V. Mosby, 1986
 Buku Teks