"Strength and Design". Centuries of Civil Engineering: A Rare Book Exhibition Celebrating the Heritage of Civil Engineering. Linda Hall Library of Science, Engineering & Technology. Diarsipkan dari versi asli tanggal 2010-11-13. Diakses tanggal 2014-08-08.[halaman dibutuhkan]
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"Strength and Design". Centuries of Civil Engineering: A Rare Book Exhibition Celebrating the Heritage of Civil Engineering. Linda Hall Library of Science, Engineering & Technology. Diarsipkan dari versi asli tanggal 2010-11-13. Diakses tanggal 2014-08-08.[halaman dibutuhkan]