Adler, Bill, author
American Management Association, 2006
eBooks
Scott, Kim, author
Pan Books, 2019
Buku Teks
Tam, Marilyn, author
Gramedia Pustaka Utama, 2007
Buku Teks
Arden, Paul, author
Phaidon, 2003
Buku Teks
National Geographic Society, 2007
Buku Referensi