Não informado. (2014). Geological Survey Professional Paper. U.S. Geological Survey Professional Paper.
Παραπομπή σε μορφή Chicago (17η εκδ.)Não informado. Geological Survey Professional Paper. Washington: U.S. Geological Survey Professional Paper, 2014.
Παραπομπή σε μορφή MLA (8th εκδ.)Não informado. Geological Survey Professional Paper. U.S. Geological Survey Professional Paper, 2014.
Πρόσοχή: Οι παραπομπές μπορεί να μην είναι 100% ακριβείς.