Typographical error Huifang Huang, Beijing Jiaotong University 15 September 2014 There is a typographical error in Section Acknowledgements. In the sentence “This work was supported by the National Natural Science Foundation of China (Grant No. 61300073, 20970777),…”, 20970777 should be 30970777. Competing interests None declared
Typographical error
15 September 2014
There is a typographical error in Section Acknowledgements. In the sentence “This work was supported by the National Natural Science Foundation of China (Grant No. 61300073, 20970777),…”, 20970777 should be 30970777.Competing interests
None declared