Não informado. (1913). Economic series. British Museum of Natural History.
Chicago-viite (17. p.)Não informado. Economic Series. London: British Museum of Natural History, 1913.
MLA-viite (8. p.)Não informado. Economic Series. British Museum of Natural History, 1913.
Varoitus: Nämä viitteet eivät aina ole täysin luotettavia.