metrological characters of research literature in a certain field ( 8 ). Analytic tools include CiteSpace, Pajek, UCINET, VOSviewer and so on, with CiteSpace being the most popular. CiteSpace was initially developed by Chaomei Chen in 2004 ( 9 ). It has been
Tianping Zhou, Yihong Xu, Aiai Zhang, Lan Zhou, Qing Zhang, Zhou Ji, and Weidong Xu
Junbo He, Tingkui Wu, Chen Ding, Beiyu Wang, Ying Hong, and Hao Liu
quantitatively evaluate trends in research in a certain field. The number of citations per paper is one of the markers of scientific merit. 9 , 10 A high number of citations indicates the influence of a paper on knowledge development. VOSviewer is a software
Minghe Yao, Tingkui Wu, and Beiyu Wang
VOSviewer (version 1.6.17) and CiteSpace (version 5.8.R3) were utilized to analyze the retrieved text files. CiteSpace and VOSviewer parameter settings can be found in Supplementary information 2. VOSviewer is a program presented by Nees Jan van Eck and
