APA (7e ed.) Bronvermelding

Não informado. Topographic and Geologic Atlas of Pennsylvania. Pennsylvania Geological Survey.

Chicago (17e ed.) Bronvermelding

Não informado. Topographic and Geologic Atlas of Pennsylvania. Harrisburg, Pa: Pennsylvania Geological Survey.

MLA (8e ed.) Bronvermelding

Não informado. Topographic and Geologic Atlas of Pennsylvania. Pennsylvania Geological Survey.

Let op: Deze citaties zijn niet altijd 100% accuraat.