I've followed the specification, I thought.
There's a link href rel=amphtml in this page that points to the AMP version, yet three days after implementing it, submitting both pages to Google, and waiting, Webmaster Tools still tells me I have no AMP pages and the AMP pages don't exist on a Google search.
What's up?
As John Mueller points out here: https://plus.google.com/+JohnMueller/posts/bwnHgShgDm7 it takes about a week for the Search Console's report to update.
You can see that your page is in the Google AMP Cache by looking at: https://cdn.ampproject.org/c/media.info/radio/opinion/finland-a-radio-app-that-does-more-than-youd-expect-2/amp