Text and Data Mining valid from 2019-03-18
First Online: 18 March 2019
Compliance with ethical guidelines
: C. Fang is co-founder of Lifespans Ltd. H. Cai serves as a paid consultant to AK Medical and Koln 3D Medical Technology. E. Kuong, E. Chui, Y.C. Siu, T. Ji and I. Drstvenšek declare that they have no competing interests.
: This article does not contain any studies with human participants or animals performed by any of the authors.