Text and Data Mining valid from 2019-01-15
Received: 3 September 2018
Accepted: 21 December 2018
First Online: 15 January 2019
Compliance with ethical standards
: Ka Keat Lim, David Bruce Matchar, Jia Loon Chong, William Yeo, Tet Sen Howe, and Joyce SB Koh declare that they have no conflict of interest.