Like most websites, this site has many links throughout it. Some links point to resources located within this website, and others to external websites (ones that are not ours). In most cases, your browser permitting, the internal links are styled using the usual method that most browsers use—blue coloured links that you haven't visited, purple links that you've recently visited, and external links have been styled to appear a bit differently—bright red colouring for unvisited links, and dark red for recently visited links; and for all of those cases, they're all underlined.
This is only a quick hint at the type of link, you can always see where a link goes to with the usual way your browser shows you link destinations (commonly, you do this by just hovering a mouse pointer over a link, and waiting a moment).
Links to external sites should not be considered as any form of endorsement, they're merely research references.
Part of that is normal—browsers rarely produce identical renditions of what you see on the screen, even quite different results are very often seen—but there shouldn't be any errors. It's not unusual for browsers to not print any background images or colours, though most do have configuration options about that. And the default website styling effects have been set to not print the bottom-of-page sort of inter-page navigation menus, and to make any in-line links written in the middle of the text look the same as the surrounding text, for neatness sake, and you can't click on a link on a printed page, anyway.
Despite these little flourishes in styling, the pages should work fine with all browsers. Nothing particularly fancy has been done on the pages that should exclude some browsers, though anybody having problems with the page rendition is welcome to contact the webmaster about it.