1. (whatiscopyright.org, 2017) tomado de: https://whatiscopyright.org/what-is-a-copyright/

2. (aulatecnologica.com, 2016) tomado de:

https://aulatecnologica.com/que-es-una-licencia-de-software/

3. (rockcontent.com, 2020) tomado de:

https://rockcontent.com/es/blog/tipos-de-software/

4. (Spotify.com, 2020) tomado de:

https://www.spotify.com/co/