http://www.iwm.org.uk/history/podcasts/voices-of-the-first-world-war/podcast-39-weapons-of-war
http://www.iwm.org.uk/history/podcasts/voices-of-the-first-world-war/podcast-13-gas-attack-at-ypres
http://deredactie.be/permalink/1.2304283 (Fritz Haber de vader van de gasoorlog)