Hendrik Antoon Lorentz, Albert Einstein, Hermann Minkowski, Hermann Weyl, Arnold Sommerfeld (1952). “The Principle of Relativity: A Collection of Original Memoirs on the Special and General Theory of Relativity”, p.75, Courier Corporation
Samuel Taylor Coleridge, William Wordsworth (2015). “Lyrical Ballads and other Poems by Samuel Taylor Coleridge and William Wordsworth (Including Their Thoughts On Poetry Principles and Secrets): Collections of Poetry which marked the beginning of the English Romantic movement in literature, including poems The Rime of the Ancient Mariner, The Dungeon, The Nightingale, Dejection: An Ode”, p.590, e-artnow