Respiratory health effects of exposure to low-NOx unflued gas heaters in the classroom: a double-blind, cluster-randomized, crossover study

- Marks, Guy B.; Ezz, Wafaa; Aust, Nathan; Toelle, Brett G.; Xuan, Wei; Belousova, Elena; Cosgrove, Carman; Jalaludin, Bin; Smith, Wayne T.