Figure 4.

(A) The author co-citation network. The configurations set as: pruning pathfinder, algorithm log-likelihood rate (LLR), time slice l, top N 50 per year, link-retaining factor (LRF) = 3, look back years (LBY) = 5, and e l = 1. The node size referred to the number of citations of a specific author, while the links represented the frequency of the co-citation for two authors. The higher betweenness centrality (betweenness centrality > 0.l) represented the leading researchers and was expressed as a purple circle around the node. (B) The top 6 co-cited author with annul citation counts.