Jacquemin B, Sunyer J, Forsberg B, Aguilera I, Briggs D, Garcia-Esteban R, Gotschi T, Heinrich J, Jarvholm B, Jarvis D, Vienneau D, Kunzli N. Home outdoor NO2 and new onset of self-reported asthma in adults. Epidemiology. 2009 Jan;20(1):119-26. doi: 10.1097/EDE.0b013e3181886e76