Funding for this research was provided by:
Kementerian Riset, Teknologi dan Pendidikan Tinggi (0045/E3/LL/2018)
Text and Data Mining valid from 2019-05-07
Received: 18 November 2018
Accepted: 22 March 2019
First Online: 7 May 2019
: The authors declare that they have no competing interests.
: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.