Lehman، Paul R. (Fall 1997). "Blue Mountain Eagle Climbing Club". The Historical Review of Berks County. Historical Society of Berks County. مؤرشف من الأصل في 2013-11-03.
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Lehman، Paul R. (Fall 1997). "Blue Mountain Eagle Climbing Club". The Historical Review of Berks County. Historical Society of Berks County. مؤرشف من الأصل في 2013-11-03.