Text and Data Mining valid from 2018-12-01
Received: 21 September 2018
Accepted: 30 October 2018
First Online: 10 December 2018
Ethics approval and consent to participate
: Ethics approval was not required for this study. Consent was not sought from participants because, whether dead or alive, their fictional nature would preclude them from providing valid informed consent.
: Not applicable.
: The authors declare that they have no competing interests.
: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.