Cessation of smoking trial in the emergency department (CoSTED): protocol for a multicentre randomised controlled trial oleh Alasdair Gray, Tim Coats, Caitlin Notley, Linda Bauld, Allan B Clark, Adrian A Boyle, Mei-See Man, Geraint Morris, Steve Parrott, Richard Holland, Ian Pope, Pippa Belderson, Emma Ward, Sanjay Agrawal, Lucy Clark, Ben M Bloom