Fondell E, Balter O, Rothman KJ. Dietary intake and supplement use of vitamins C and E and upper respiratory tract infection. J Am Coll Nutr. 2011 Aug 1;30(4):248-58.
Merrill RM, Madanat H, Kelley AT, Layton JB. Nurse and physician patient counseling about tobacco smoking in Jordan. Promot Educ. 2008 Sep;15(3):9-14. doi: 10.1177/1025382308095649
Cropper ML, Haile M, Lampietti J, Poulos C, Whittington D. The demand for a malaria vaccine: evidence from Ethiopia. J Dev Econ. 2004 Oct 1;75(1):303-18.