McCarty, Thomas
Six sigma for sustainability : how organizations design and deploy winning environmental programs
McGraw-Hill, 2011
 Buku Teks
Strategi bisnis six sigma
Manajemen Usahawan Indonesia, XXXII (01) Januari 2003: 47-49, 2003
 Artikel Jurnal
Hopfenbeck, Waldemar
The green management revolution : lessons in environmental excellence
[publisher not identified], [date of publication no identified]
 Buku Teks
George, Michael L.
Lean six sigma for service : how to use lean speed and six sigma quality to improve services and transactions
McGraw-Hill, 2003
 Buku Teks
Utilizing six sigma to improve the processing time : a simulation study at an emergency departement
by Nabeel Mandahawi, Mohammed Shurrab, Sameh Al-Shihabi, Abdallah A. Abdallah and Yousuf M. Alfarah
Taylor and Francis, 2017
 Artikel Jurnal