Citation Verified Memento
📖 http://www.latimes.com/business/la-fi-amazon-walmart-20150724-story.html 2018.06.21
📖 https://www.census.gov/mrts/www/data/pdf/00Q4.pdf 2018.06.21
📖 http://money.cnn.com/2017/03/29/technology/amazon-sales-tax/index.html 2018.06.21
📖 https://www.fastcompany.com/27309/whos-writing-book-web-business 2018.06.21