I think you can get around the messed-up-link problem in at least two ways. First, write some link text, select it and use the make-a-link button like this. Second, use Markdown: link text in square brackets immediately followed by link URL in parens like this. If I’ve guessed correctly, those should both be links to the Polya thing you were hoping to link to.
[EDITED to add: hmm, first one works (once I fixed a wrong guess at what the URL was meant to be) but second one doesn’t function as a link at all, which I suspect may be a Markdown bug. … And on further investigation, my further attempts at making links with Markdown syntax all fail completely—they don’t even try to turn into links and I have no idea why. This happens not only in this comment but also elsewhere, so it surely isn’t a side-effect of the messed-up link above.]
I think you can get around the messed-up-link problem in at least two ways. First, write some link text, select it and use the make-a-link button like this. Second, use Markdown: link text in square brackets immediately followed by link URL in parens like this. If I’ve guessed correctly, those should both be links to the Polya thing you were hoping to link to.
[EDITED to add: hmm, first one works (once I fixed a wrong guess at what the URL was meant to be) but second one doesn’t function as a link at all, which I suspect may be a Markdown bug. … And on further investigation, my further attempts at making links with Markdown syntax all fail completely—they don’t even try to turn into links and I have no idea why. This happens not only in this comment but also elsewhere, so it surely isn’t a side-effect of the messed-up link above.]