城市空气质量信息公开指数发布 6城市得分为零 (Urban Air Quality Information Transparency Index: Most Cities Limit Level of Info Released, Six Cities Score 0) 21st Century Business Herald, October 24, 2012 http://www.21cbh.com/HTML/2012-10-24/yNNjUxXzU0NjIyNg.html