Google Calendar "other calendars" XML feeds

I'm building a webapp 开发者_如何转开发that leverages gdata-api to bring a user's calendars into the application. I'd like to also be able to bring their other calendars in as well, but can't find an XML feed for some of them.

I've noticed that not all of the "other calendars" in Google Calendar have XML feeds. For instance, over a year ago I subscribed to a calendar called "MNT", which is the US Men's National Team (soccer). When I go into settings, this calendar has XML, ICAL, and HTML addresses.

But if I click the Add link under "Other Calendars" and browse for interesting calendars, select Sports -> Soccer -> EPL -> Manchester United and subscribe to it, it only has an HTML address. So far, all of the other calendars I've tried only have HTML addresses.

Is there a way to get an XML feed from these calendars that only display an HTML address?

Is there a better place to find XML calendar feeds than Add -> Interesting Calendars?

Thanks!

I believe that this is due to licensing issues for calendars such as the sports one. That's certainly why you can't sync sports calendars to mobile devices using Google Sync.

Some of the "interesting" calendars do have XML feeds, such as UK Public Holidays and Phases of the Moon.