Ziglar, Zig
Steps to the top
Heinemann Asia, 1995
Buku Teks
Ray, James Arthur
Harmonic wealth: the secret of attracting the life you want = kekayaan harmonis rahasia menciptakan kehidupan yang anda inginkan
Gramedia Pustaka Utama, 2009
Buku Teks
O`Neil, John R.
The paradox of success : when winning at work means losing at life : a book of renewal for manager and leaders
McGraw-Hill, 1995
Buku Teks
Haig, Matt
If you're so brilliant... how come you don't have an e-strategy?: kunci sukses bisnis online / Matt Haig; penerjemah, Andreas Haryono
Elex Media Komputindo,
Buku Teks
Humes. James C.
Talk your way to the top/ James C. Humes
McGraw-Hill , 1980
Buku Teks