Sorry, for writing in English. It would be great if you could add a translation.
In the near future, editors and readers can get pop-ups for references in the same style as Page Previews: The feature called Reference Previews will soon be deployed to a first group of wikis as a default feature.
Reference Previews show you a reference in a small pop-up when you hover over the reference number in square brackets. This way, you can look up a reference without jumping down to the bottom of the page. Nearly 2,000 people on eu.wikipedia are currently testing Reference Previews as a beta feature. After many months of testing, bug fixing and other improvements, the feature will soon be enabled as a default feature on German, Arabic and Hebrew Wikipedia, probably on May 5.
Would Basque Wikipedia also want to get the feature early? We were thinking it would be a good candidate because on Basque Wikipedia, there is no default gadget for previewing references yet. (Here’s a link to translatewiki, where the interface of the feature can be translated).
If you want to know more about the feature, please have a look at the project page or write me a message on my talk page. We would be very happy to have Basque Wikipedia on board!
--Johanna for the Technical Wishes team at Wikimedia Germany