Links:
[1] https://www.digi-sign.com/downloads/download.php?id=aacd-digi-ssl-pdf
[2] https://www.digi-sign.com/digi-ssl
[3] https://www.digi-sign.com/digi-trust/trusted+services+provider
[4] https://www.digi-sign.com/https
[5] https://www.digi-sign.com/digi-ca/service
[6] https://www.digi-sign.com/digi-ca/server
[7] https://www.digi-sign.com/en/aacd/index
[8] https://www.digi-sign.com/taxonomy/term/23