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Combined search results
| Database or search engine | Number of search results |
|---|---|
| ACM Digital Library | 4 |
| Compendex | 80 |
| IEEE Explore | 13 |
| ScienceDirect | 12 |
| Scopus | 79 |
| Springer | 118 |
| Web of Science | 48 |
| Combined studies | 354 |
| Repeated studies | 216 |
| Total of studies after removing repeated results | 138 |
