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By: Heyl, Paul RType: ArticleIn: Proceedings of the American Philosophical Society held at Philadelphia for promoting useful knowledgeVolume: 49Series:Issue: 194Date: 1910Page Range: 49--51Publication Info: Philadelphia, American Philosophical Society,Subjects:
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By: Heyl, Paul RType: ArticleIn: Proceedings of the American Philosophical Society held at Philadelphia for promoting useful knowledgeVolume: 52Series:Issue: 208Date: 1913Page Range: 21--30Publication Info: Philadelphia, American Philosophical Society,Subjects:
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By: Heyl, Paul R - Briggs, Lyman J. (Lyman James),Type: ArticleIn: Proceedings of the American Philosophical Society held at Philadelphia for promoting useful knowledgeVolume: 61Series:Issue: 220Date: 1922Page Range: 15--32Publication Info: Philadelphia, American Philosophical Society,Subjects: