## 3 Results
### Research
#### 3.4.8 Research on ESD Integration and Implementation  
[PERSON] [116] presented a developed evidence-based model (the I3E model) that could be used to embed ESD in an HEI, based on doctoral research on organizational learning and change process at a specific HEI to build ESD into the HEI's curriculum. [PERSON] et al. [117] investigated the ESD transition factors in Central European HEIs and provided insights into the similarities and differences at the national level and the overall trends in the region. The authors identified a lack of research on ESD at the HEI level in post-socialist countries. [PERSON] et al. [118] described the ESD integration process in HEIs in a specific country as well as the integration approaches, challenges faced and overcome, and the critical success factors. In particular, the authors emphasized that the Quality Assurance Agency (QAA) and the Higher Education Academy (HEA) could be used as guides to promote the ESD agenda. After reviewing the evolution of ESD in international declarations, [PERSON] [119] highlighted the obstacles regarding the implementation of ESD and curriculum greening in HEIs. By performing a case study, [PERSON] and [PERSON] [120] provided information about other HEIs striving to create similar HEI-wide sustainability requirements. The authors shared their experiences with incorporating sustainability into a general education curriculum. [PERSON] [121] presented the conclusions and 10 practical strategies to foster education for sustainability, which were derived from a research project on education for sustainability in higher education.  
[PERSON] et al. [122] highlighted the challenges facing ESD implementation in teaching education institutions in a specific country. The authors also provided recommendations and solutions that can be applied in ESD teaching education in developing countries, indicating that future research is required to examine the role of non-formal educational educators, e.g., NGOs, in training teachers in ESD. [PERSON] et al. [123] described the use of project-based learning as a tool to support integrative approaches to sustainability in the context of higher education, providing examples of successful approaches and trends that characterize this form of learning. Our review indicates that more research is needed to develop measures to evaluate the impact of such approaches and to explore the potential for projects integrated into the curriculum to result in outputs that benefit wider communities.  
[PERSON] and [PERSON] [124] investigated how ESD initiatives were delivered in formal education, campus management, and extra-curricular activities in two HEIs. Good practices were also highlighted in this paper. Using the Copernicus charter principles, [PERSON] and [PERSON] [125] assessed the higher education practices in a specific transition country and identified weaknesses in its higher education system that inhibit the ESD. The authors also recommended strategic interventions that could lower the negative impact of the weaknesses on ESD. By examining ESD drivers in higher education in a specific country, [PERSON] and [PERSON] [126] identified government support and encouraging leadership development for sustainability amongst HEI executives as critical factors that strengthens sustainability efforts. [PERSON] et al. [127] studied economic higher education in a specific country and measured the level of SD implementation in programs, projects, debates, and courses. The authors proposed to identify clear ways to implement ESD in HEIs in this country, considering the labor market requirements and the transition to a green, sustainable economy. A full summary of articles focusing on research on integration and implementation of ESD in HEIs is presented in Table 8.