1. FreeCodeCamp (2017).
https://www.freecodecamp.org/news/a-hacker-stole-31m-of-ether-how-it-happened-and-what-it-means-for-ethereum-9e5dc29e33ce/
2. Nearest neighbors (2018).
http://scikit-learn.org/stable/modules/neighbors.html
3. Xgboost (2018).
http://xgboost.readthedocs.io/en/latest/python/python_api.html
4. Contracts with verified source codes only (2019).
https://etherscan.io/contractsVerified?filter=opensourcelicense
5. Cryptoscamdb (2019).
https://documenter.getpostman.com/view/4298426/RzZ7nKcM?version=latest