O’Shea, O. K., H. J. Green, H. L. Philpott, and N. Newland. “An Exploratory, Randomised, Crossover Study to Investigate the Effect of a Nicotine Containing Electronic Cigarette on Appetite in Healthy Adult Smokers, After a Period of Smoking Abstinence: Study Protocol”. International Journal of Clinical Trials, vol. 9, no. 4, Oct. 2022, pp. 314-20, doi:10.18203/2349-3259.ijct20222692.