--- https://www.cmaj.ca/content/193/2/E63.long 2021 Canada coronavirus infections pneumonia, viral journal article data collection ontario chronology operative procedure, nos causation general surgery causality Surgery chronology pandemics COVID-19
--- https://rmlg.uliege.be/article/2779 2016 Belgium teaching material journal article postman students time factors medical history taking chronology student, nos chronology