Rogers, Katherine M
Harvester Wheatsheaf, 1990
Buku Teks SO
Yanagita, Kunio
New service, 1968
Buku Teks
Allende, Isabel
Gramedia Pustaka Utama , 2012
Buku Teks SO
Rifelly Dewi Astuti
University of Indonesia, 2012
Artikel Jurnal
Lestari Agusalim
Faculty of Economic and Business UIN Syarif Hidayatullah, 2018
Artikel Jurnal