Lillienberg L, Zock JP, Kromhout H, Plana E, Jarvis D, Toren K. A population-based study on welding exposures at work and respiratory symptoms. Ann Occup Hyg. 2008 Mar;52(2):107-15.
Cassingham KM, Sills EO, Pattanayak SK, Mansfield CA. Voluntary conservation of North Carolina's natural heritage. J For. 2002;100(5):16-23.