1. Alexa. Top 1M sites. https://www.alexa.com/topsites May 24 2018. http://s3.dualstack.us-east-1.amazonaws.com/alexa-static/top-1m.csv.zip. Alexa. Top 1M sites. https://www.alexa.com/topsites May 24 2018. http://s3.dualstack.us-east-1.amazonaws.com/alexa-static/top-1m.csv.zip.
2. Cisco. Umbrella Top 1M List. https://umbrella.cisco.com/blog/blog/2016/12/14/cisco-umbrella-1-million/. Cisco. Umbrella Top 1M List. https://umbrella.cisco.com/blog/blog/2016/12/14/cisco-umbrella-1-million/.
3. Majestic. https://majestic.com/reports/majestic-million/ May 17 2018. Majestic. https://majestic.com/reports/majestic-million/ May 17 2018.