1. Merriam-Webster. Online dictionary of the English language. Accessed 5 May 2010.
2. Long CW. An account of the first use of sulphuric ether by inhalation as an anæsthetic in surgical operations. South Med Surg J. 1849;5:705–13.
3. Simpson JY. On a new anæsthetic agent, more efficient than sulphuric ether. Lancet. 1847;2:549–50.
4. Macewen W. Clinical observations on the introduction of tracheal tubes by the mouth instead of performing tracheotomy or laryngotomy. Br Med J. 1880;2:122–4, 163–5.
5. Röntgen WC. Über eine neue Art von Strahlen. Sitzungsberichte der Physikalischmedizinischen Gesellschaft zu Würzburg. 1895;137.