Analysis of information sources in references of the Wikipedia article "二手煙" in Chinese language version.
Secondhand smoke exposure causes disease and premature death in children and adults who do not smoke（页面存档备份，存于互联网档案馆）
Parties recognize that scientific evidence has unequivocally established that exposure to tobacco causes death, disease and disability
Secondhand smoke exposure causes disease and premature death in children and adults who do not smoke（页面存档备份，存于互联网档案馆）
Parties recognize that scientific evidence has unequivocally established that exposure to tobacco causes death, disease and disability
