Justus von Liebig (1855). “Principles of agricultural chemistry with special reference to the late researches made in England: By Justus von Liebig. (Ed. by William Gregory)”, p.31
Walter Scott (2015). “Heroes of the Scottish Highlands: Ivanhoe, Waverley and Rob Roy (3 Unabridged Illustrated Classics): Historical Novels from the Author of The Pirate, The Heart of Midlothian, Old Mortality, The Guy Mannering, The Antiquary, The Bride of Lammermoor and Anne of Geierstein”, p.204, e-artnow
Robert Louis Stevenson (2015). “Collected Memoirs, Travel Sketches and Island Literature of Robert Louis Stevenson: Autobiographical Writings and Essays by the prolific Scottish novelist, poet and travel writer, author of Treasure Island, The Strange Case of Dr. Jekyll and Mr. Hyde, Kidnapped & Catriona”, p.452, e-artnow