## 3 Results
### Outreach and Collaboration
#### 3.5.1 Sustainability-Oriented HEI Networks  
A summary of the articles from the outreach and collaboration category that targeted sustainability-oriented HEI networks is represented in Table 10. These articles are addressed below in more detail.  
[PERSON] et al. [145] collected information on 14 HEI networks, describing their structures, roles, relationships, and activities. [PERSON] et al. [146] described SD courses offered in European HEI academic learning networks. [PERSON] et al. [147] proposed an analytical framework that could be used to describe HEI networks more categorically, identifying 15 characteristics from the literature to develop this framework, which the authors then applied to two sustainability-oriented HEI networks. Our review indicates that applying the proposed framework to other HEI networks and adapting it accordingly would be an excellent subject for future research.  
[PERSON] and [PERSON] [148] studied a specific HEI network, asking how sustainability was promoted in postgraduate education and research and how this network was used to share and expand experience in ESD. The paper provides an overview of initiatives and issues faced by the HEIs involved. [PERSON] and [PERSON] [8] described how sustainability is interpreted in HEI networks and found that \"greening\" is the dominant sustainability topic discussed in these networks, followed by \"resilience\" and \"alternative.\" [PERSON] et al. [149] provided an example of an HEI learning network that addresses a specific sustainability issue. The authors provided the theoretical background, initial actions, and expected outcomes for this network. In general, our review shows that the sustainability-oriented HEI networks play important roles in the sustainability transition, generating added value for all network members. These networks generate social capital through cooperation, but the nature and the role of this capital requires further investigation. They also have a cumulative impact, because they tend to facilitate the initiation, support of, realization of, and reporting on SD policies launched at global, regional, or institutional levels. However, no comparative assessment of different HEI networks has been conducted.  
\begin{table}
\begin{tabular}{c c c} \hline \hline
**Article** & **Research Theme(s)** & **Research Method(s)** \\ \hline [PERSON] et al., 2018 [145] & Sustainability-oriented HEI networks & Desktop research, survey, and workshop \\ \hline [PERSON] et al., 2013 [146] & SD oriented courses within the academic learning networks & Case studies \\ \hline [PERSON] et al., 2018 [147] & Sustainability-oriented HEI networks & Case study \\ \hline [PERSON] and [PERSON] 2011 [148] & HEI network for promotion of sustainability in postgraduate education and research & Case study \\ \hline [PERSON] and [PERSON] 2020 [8] & Main traits of sustainability discourses and practices promoted by the selected HEI networks & Content analysis \\ \hline [PERSON] et al., 2015 [149] & Learning network & Case study \\ \hline \hline \end{tabular}
\end{table}
Table 10: Articles from the outreach and collaboration category focusing on sustainability-oriented HEI networks.