Management Strategy
book: Strategic Management and Competitive Advantage by Jay B. Barney; William S Hesterly.
article 1:
http://www.theverge.com/2015/9/22/9372563/dropbox-really-is-a-feature
article 2:
1: http://www.bloomberg.com/news/articles/2015-09-28/keurig-introduces-new-kold-brewer-to-compete-with-sodastream-if4jfra8
2: http://www.bloomberg.com/news/articles/2015-06-15/sodastream-ceo-dismisses-new-keurig-kold-machine-as-competition
3: http://www.fool.com/investing/general/2015/06/18/why-the-keurig-kold-is-no-threat-to-sodastream-int.aspx