1. Kinsella, B, Juniper estimates 3.25 billion voice assistants are in use today, google has about 30% of them. https://voicebot.ai/2019/02/14/
2. Smith, S, Digital voice assistants in use to triple to 8 billion by 2023, driven by smart home devices. www.juniperresearch.com
3. Alexa goes to college (2018) Echo dots move into dorms on campus. https://www.usatoday.com/story/money/2018/09/06/college-students-echo-dots-dorm-rooms/1087251002/, [accessed 10-August-2020]
4. Welch (2018) Amazon made a special version of alexa for hotels that put echo speakers in their rooms. https://www.theverge.com/2018/6/19/17476688/amazon-alexa-forhospitality-announced-hotels-echo/
5. Voicebot.ai (2020) Nearly 90 million u.s. adults have smart speakers, adoption now exceeds one-third of consumers. https://voicebot.ai/2020/04/28/nearly-90-million-u-s-adults-have-smart-speakers-adoption-now-exceeds-one-third-of-consumers/. [Online; accessed 10-May-2020]