1. Abadilla, E. V. (2016, November 21). Profile of commuters at LRT1 unveiled. Manila Bulletin.
https://business.mb.com.ph/2016/11/21/profile-of-commuters-at-lrt1-unveiled/
. Accessed 8 July 2018.
2. Ambrus, A., Calvano, E., & Reisinger, M. (2014). Either or both competition: a ‘two-sided’ theory of advertising with overlapping viewerships. American Economic Journal: Microeconomics, 8(3), 189–222.
3. Appleton, J. H. (1962). The geography of communications in Great Britain. London: Oxford University Press.
4. Baker, L. E. (2007). Public sites versus public sights: The progressive response to outdoor advertising and the commercialization of public space. The American Studies Association: American Quarterly, 59(4), 1187–1213.
5. Blackwell Reference Online. (2008).
http://www.blackwellreference.com/public/tocnode?id=g9781405131995_yr2015_chunk_g97814051319958_ss68-1
. Accessed 05 June 2018.