Advice
Tolstoy, Leo. Tolstoy's Diaries, edited and translated by R. F. Christian. Vol. 1, Faber and Faber, 2010. Originally diary entry, 6 Jan. 1854.
Pericles. Quoted in "Pericles." Parallel Lives by Plutarch. c. 2nd century BC, ch. 18, sect. 2.
Pericles. Quoted in "Pericles." Parallel Lives by Plutarch. Oxford University Press, 2009, ch. 18, sect. 2.
Bakr, Abu. Quoted in "Sayings of Abu Bakir." Examining Religions: Islam, written by Ruqaiyyah Waris Maqsood. Heinemann Educational, 2008.
Horace. Carmina [Odes]. 23 BC, bk. 4, no. 12.
Horace. "Odes." The Complete Odes and Epodes, translated by David West. Oxford University Press, 2008, bk. 4, no. 12.
Horace. Epistularum liber primus [First Book of Letters]. 20 BC, bk. 1, epistle 2.
Horace. "Epistles." Satires and Epistles, translated by John Davie. Oxford University Press, 2011, bk. 1, epistle 2.
Horace. Epistularum liber secundus [Second Book of Letters]. 14 BC, bk. 2, epistle 2.
Horace. "Epistles." Satires and Epistles, translated by John Davie. Oxford University Press, 2011, bk. 2, epistle 2.
Horace. Carmina [Odes]. 23 BC, bk. 1, no. 11.
Horace. "Odes." The Complete Odes and Epodes, translated by David West. Oxford University Press, 2008, bk. 1, no. 11.
Blake, William. "Proverbs of Hell." The Marriage of Heaven and Hell. c. 1790.
Blake, William. "The Marriage of Heaven and Hell." The Complete Poetry and Prose of William Blake, edited by David V. Erdman. University of California Press, 2008.
Longfellow, Henry Wadsworth, [published anonymously]. "A Psalm of Life." The Knickerbocker. New York: Lewis Gaylord Clark, Oct. 1838, I. 33.
Longfellow, Henry Wadsworth. "A Psalm of Life." Henry Wadsworth Longfellow: Poems and Other Writings, edited by J. D. McClatchy. Library of America, 2000, I. 33.
Matthew 6:31
The Holy Bible, New International Version. International Bible Society, 1978. (Matthew 6:31).
Hemingway, Ernest. The Old Man and the Sea. Charles Scribner's Sons, 1952.
Horace. Carmina [Odes]. 23 BC, bk. 1, no. 9.
Horace. "Odes." The Complete Odes and Epodes, translated by David West. Oxford University Press, 2008, bk. 1, no. 9.
Pindar. Pythian Odes. c. 474, pythian 3.
Pindar. The Complete Odes, translated by Anthony Verity. Oxford University Press, 2008, pythian 3.