Welcome on the TubeNet!
There are commercial editions of excerpts in books and on CD or DVD. I have the Torchinsky books myself, others are in the know on the disk versions. If you are not close to a musically well stocked bookstore (they are becoming really rare many places in the world), it may be worthwhile looking through the shelves of a good library before ordering books over the web.
I am retired and being a score-reading freak I find
http://imslp.org/wiki/Main_Page
immensely helpful. They don’t present the newer music for copyright reasons, and they do not always offer parts along with the scores. But as a sample the tenor and bass tuba parts from The Planets recently discussed on TN may be found via the given link. The search function is on the left of the main page. You may have to scroll a bit depending on your monitor.
I am not entirely aware whether it is my age causing your link going to a forbidden page, when I click it?
Klaus