Eisenmann, Thomas R.; Parker, Geoffrey; Van Alstyne, Marshall (August 31, 2008). "Opening Platforms: How, When and Why?" (PDF). Harvard Business School Entrepreneurial Management Working Paper No. 09-030. Harvard Business School. p. 2. doi:10.2139/ssrn.1264012. Retrieved 2015-06-30. http://www.hbs.edu/faculty/Publication%20Files/09-030.pdf
Eisenmann, Thomas R.; Parker, Geoffrey; Van Alstyne, Marshall (August 31, 2008). "Opening Platforms: How, When and Why?" (PDF). Harvard Business School Entrepreneurial Management Working Paper No. 09-030. Harvard Business School. p. 2. doi:10.2139/ssrn.1264012. Retrieved 2015-06-30. http://www.hbs.edu/faculty/Publication%20Files/09-030.pdf
Eisenmann, Thomas R.; Parker, Geoffrey; Van Alstyne, Marshall (August 31, 2008). "Opening Platforms: How, When and Why?" (PDF). Harvard Business School Entrepreneurial Management Working Paper No. 09-030. Harvard Business School. p. 2. doi:10.2139/ssrn.1264012. Retrieved 2015-06-30. http://www.hbs.edu/faculty/Publication%20Files/09-030.pdf