Use of scratchcards for allocation concealment in a prehospital randomised controlled trial
Leigh Keen, Jenna Katherine Bulger, Nigel Rees, Helen Snooks, Greg Fegan, Simon Ford, Bridie Angela Evans, Mirella Longo
Emergency Medicine Journal Nov 2018, 35 (11) 708-710; DOI: 10.1136/emermed-2018-207881