Siau, K., Li, J., Fisher, N. C., Mulder, C. J. and Ishaq, S. (2017) “Intubation Failure During Gastroscopy: Incidence, Predictors and Follow-Up Findings”, Journal of Gastrointestinal and Liver Diseases, 26(4), pp. 339–344. doi: 10.15403/jgld.2014.1121.264.isq.