What material to use for the spine in the binding of a paperback book? I want to bind a few paperbacks whose sheets have gone loose. Let's say I have already removed all the old glue and I have only loose sheets, with their edges trimmed. I have seen several video tutorials and the procedure is - up to a point - apparently clear to me. (I can post the link to the youtube videos if it can help).

I already have the glue (PVA, ph-neutral for book-binding) but I don't know where to look for the tissue that is used to bind the spine. In some tutorials it appears to be a strip of tissue (not different from a cotton t-shirt). In others they say they use "Japanese tissue", which I have been unable to find. 





To be clear, its the tissue that is placed on the spine after gluing the pages, and sometimes before adding more glue on top of it.

Since I am willing to bind several such paperbacks, can you suggest a material that has the desired properties (I guess resistance, ability to absorb glue and bind to it) and has a reasonable quality/price ratio?

I am not asking for specific commercial products but at least to be able to know where to go to find it (hardware stores? painting stores? bookstores? drug dealers?) and what to ask for.
I have used both of these when I bound my hardcover books. I am unsure if either of these are what you have pictured though

Bookbinding cloth

Also known as book cloth or Japanese book cloth. These are paper backed materials, which make it good for applying adhesives, and usually are made special designs. I have use this for just the spine for flair and to make the material last longer (used for more books). 

Cheese cloth

This is easier to come by, since it is not exclusively a craft item , and works relatively well. These come in a variety of grades and the finer ones would be preferred for this task. 

Both of these should fit your criteria