1. Liu, C., Xia, X., Lo, D., Gao, C., Yang, X., Grundy, J.: Opportunities and challenges in code search tools. ACM Comput. Surv. (CSUR) 54(9), 1–40 (2021)
2. Linstead, E., Rigor, P., Bajracharya, S., Lopes, C., Baldi, P.: Mining internet-scale software repositories. In: Advances in Neural Information Processing Systems, vol. 20 (2007)
3. Lu, M., Sun, X., Wang, S., Lo, D., Duan, Y.: Query expansion via wordnet for effective code search. In: 2015 IEEE 22nd International Conference on Software Analysis, Evolution, and Reengineering (SANER), pp. 545–549. IEEE (2015)
4. Lv, F., Zhang, H., Lou, J.G., Wang, S., Zhang, D., Zhao, J.: Codehow: effective code search based on api understanding and extended boolean model (e). In: 2015 30th IEEE/ACM International Conference on Automated Software Engineering (ASE), pp. 260–270. IEEE (2015)
5. Biggerstaff, T.J., Mitbander, B.G., Webster, D.E.: Program understanding and the concept assignment problem. Commun. ACM 37(5), 72–82 (1994)