Taliya Imaniya
2019
UI - Skripsi Membership
Khairana Izzati
Fakultas Ekonomi dan Bisnis Universitas Indonesia, 2018
UI - Skripsi Membership
Sherman, Jerry
Farrchila Publications, 1979
Buku Teks
Hamill, Pete
Little, Brown and Company, 2003
Buku Teks
Panggabean, Julius Ceisar
2018
UI - Tesis Membership