Não informado. Miscellaneous map series. Minnesota Geological Survey.
Chicago (17e ed.) BronvermeldingNão informado. Miscellaneous Map Series. Saint Paul, Minn: Minnesota Geological Survey.
MLA (8e ed.) BronvermeldingNão informado. Miscellaneous Map Series. Minnesota Geological Survey.
Let op: Deze citaties zijn niet altijd 100% accuraat.