Priit Kasesalu - http://en.wikipedia.org/wiki/Priit_Kasesalu

Jaan Tallinn -

1. http://en.wikipedia.org/wiki/Jaan_Tallinn
   
2. Talks and Presentations (YouTube)

Ahti Heinla - http://en.wikipedia.org/wiki/Ahti_Heinla

Interesting articles:

• Ahti Heinla - Skype founders invent self-driving robot that can deliver groceries for £1

• Skype co-creator(database) and boys' teacher Hannu Krosing's video:
  PostSQL -- using PostgreSQL as a better NoSQL by Hannu Krosing

• The Story of Skype (Stanford 2009) from Sten Tamkivi

• Barack Obama in Estonia, Tallinn 03. september 2014 [ENG]
  ''The entrepreneurial spirit of the Estonian people has been unleashed, and your innovations - like Skype — are transforming our world.''

• “How can they be so good?”: The strange story of Skype [ENG]

Additional interesting mentions:

• Jaan Tallinn's grandfather: http://www.eelk.ee/~elulood/tallinn.html [EST]

• Jaan Tallinn's speech: ''So You Want To Be a Technology Developer''

• Jaan Tallinn's presentation : "Jaan Tallinn, From Soviets to Singularity"

• Jaan Tallinn's interview : "Interview Jaan Tallinn @ Pioneers'17"

• Priit Kasesalu's accordion song created by program SoundClub: https://www.youtube.com/watch?v=-0xju5lSCOs (This is not a real accordion!!)

• Yerevan Computer Research and Development Institute: Wikipedia

• Nairi Computer
  

• Estonian history

• Russian Computer Museum [RU]: https://www.computer-museum.ru/articles/universalnie_evm/1371/