Cant install libpri

Im reading asterisk definitive guide and am stuck at installing libpri (chapter 3, page 48).
So far Ive done

$ mkdir libpri
$ cd libpri/

But I cant cant get the below step to work

$ svn co

I think using subversion didnt work so I used wget to get the source at an ealier stage. It does state that I can get the source from but I did that and all I have is index.html in my libpri folder.

Any info?

To get the current latest version of libpri, use the following URL: … .13.tar.gz

I am very new to using ubuntu. Where and how would I use the Url? ie, which command

lynx, linx, firefox, opera, wget, curl, etc. I.E. any web browser or URL downloader.