GeoEco | Faculty of Teacher Training and Education, Universitas Sebelas Maret. Cambridge University Press.
Chicago-viite (17. p.)GeoEco | Faculty of Teacher Training and Education, Universitas Sebelas Maret. Cambridge University Press.
MLA-viite (9. p.)GeoEco | Faculty of Teacher Training and Education, Universitas Sebelas Maret. Cambridge University Press.
Varoitus: Nämä viitteet eivät aina ole täysin luotettavia.