Jannis, C. Paul
N.Y. John Weley & Sons c. , 1980
Buku Teks
Hanssmann, Fred, author
John Wiley & Sons, 1962
Buku Teks
Sianipar, Dame Grace, author
Fakultas Matematika dan Ilmu Pengetahuan Alam Universitas Indonesia, 1987
UI - Skripsi (Membership)
Butters, J. Keith, author
Harvard University Graduate School of Business Administration, 1949
Buku Teks
Mochamad Jody Arafah, author
2019
UI - Skripsi (Membership)