Samuel Taylor Coleridge (1838). “The Literary Remains of Samuel Taylor Coleridge: Preface. Formula fidei de ss. Trinitate. Nightly prayer. Notes on the book of common prayer; Hooker; Field; Donne; Henry More; Heinrichs; Hacket; Jeremy Taylor; The pilgrim's progress; John Smith. Letter to a godchild”, p.186
"Epistolæ Ad Lucilium" by Marcus Fabius Quintilianus as reported in "Hoyt's New Cyclopedia Of Practical Quotations" by Jehiel Keeler Hoyt, p. 878-82., 1922.