Fig. 3
The keywords co-occurrence network. Minimum number of occurrence of a keyword = 10, minimum links strength = 10. Overall, 1638 keywords met threshold criteria. There are 7 clusters of keywords: red indicates Cluster 1 (n = 449), green indicates Cluster 2 (n = 341), blue indicates Cluster 3 (n = 285), yellow indicates Cluster 4 (n = 246), purple indicates Cluster 5 (n = 214), light-blue indicates Cluster 6 (n = 94), orange indicates Cluster 7 (n = 9)