This is really fascinating. I dug around a bit to see if I could find a digital copy of the article you mentioned. The Norwegian National Library have an impressive archive of scanned books and newspapers going back hundreds of years, but apparently no danish newspapers. Instead I found a reference to a book from 1996 by an author from New Zealand which seems to describe the same topic in great detail.

This is basically the very early, pre-internett version of what Snowden revealed. The book is made available for free by the author: http://www.nickyhager.info/Secret_Power.pdf

This old website also contains a lot of interesting information on Echelon: https://www.bibliotecapleyades.net/ciencia/echelon04.htm

The summary is quite something: «In the greatest surveillance effort ever established, the US National Security Agency (NSA) has created a global spy system, codename ECHELON, which captures and analyzes virtually every phone call, fax, email and telex message sent anywhere in the world.»

There was also made a documentary based on the book (?):https://www.youtube.com/watch?v=F-S0JH5YYZw