1. Digital in 2020, “We Are Social,” (2020), available from: https://wearesocial.com/digital-2020.
2. J. Muller, “Indonesia: number of internet users 2017-2023,” in Statista.com (2019) [accesed 2019 Nov 21].
3. Y. Pusparisa, “96% Pengguna Internet di Indonesia Pernah Menggunakan E-Commerce,” in databoks.katadata.com (2019), Available from: https://databoks.katadata.co.id/datapublish/2019/12/03/96-pengguna-internet-di-indonesia-pernah-gunakan-e-commerce, [accesed 2019 Nov 21]
4. E. Clemons, I.H. Hann, and L. M. Hitt, “The Nature of Competition in Electronic Markets: An Empirical Investigation of Online Travel Agent Offerings,” in researchgate.net (1999), pp. 1–40.
5. A. Farhan, “Milenial dan Online Travel Agent,” (2020), available from: https://travel.detik.com/travel-news/d-4863398/milenial-dan-online-travel-agent.