G.D Bell, J Weil, G Harrison, A Morden, P.H Jones, P.W Gant, J.E Trowell, A.K Yoong, T.K Daneshmend, R.F.A Logan,
14C-urea breath analysis, a non-invasive test for Campylobacter pylori in the stomach. The Lancet. ,vol. 329, pp. 1367- 1368 ,(1987) ,
10.1016/S0140-6736(87)90664-7