Não informado. Topographic and Geologic Atlas of Pennsylvania. Pennsylvania Geological Survey.
Chicago Style (17th ed.) CitationNão informado. Topographic and Geologic Atlas of Pennsylvania. Harrisburg, Pa: Pennsylvania Geological Survey.
MLA (8th ed.) CitationNão informado. Topographic and Geologic Atlas of Pennsylvania. Pennsylvania Geological Survey.
Warning: These citations may not always be 100% accurate.