Charles Sanders Peirce, Nathan Houser, Christian J.W. J. W. Kloesel (1992). “The Essential Peirce, Volume 1: Selected Philosophical Writings? (1867–1893)”, p.111, Indiana University Press
"Interior Castle" by Teresa of Avila, (Ch. 2), as translated by the Benedictines of Stanbrook (1911), revised and edited by Fr. Benedict Zimmerman, 1577.