Text and Data Mining valid from 2018-03-22
First Online: 22 March 2018
Change Date: 23 April 2018
Change Type: Corrigendum
Change Details: In the version of this article initially published, the left panel of Figure 4a was erroneously duplicated and used for both the left and right panels. However, these panels should show different graphs. The error has been corrected in the HTML and PDF versions of the article.
: The authors declare no competing financial interests.