Fig. 2. Types of collaboration between Chinese and foreign institutions (the shaded parts are considered in this article; revised according to Zhang et al. 2020).

The WCJ papers can be classified into three groups according to the institutions of authors: N-ICA, ICA, and A special category (Hong Kong, Macao, Taiwan). The ICA group can be further divided into three subgroups based on the location of the first or corresponding author’s institution. Similarly, a special category group can be subdivided into Mainland China-led and HK/Macao/Taiwan-led.