Vim: yanking between files

When working on my thesis I decided to put all the chapters in seperate files. With the folding vim does on latex files with the vim-latexsuite this is a breeze because you can easily yank whole chapters. However sometimes some lines are included that didn't belong to the chapter, like the bibliography after the conclusion. So I tried to yank these back. No luck. When moving to the new files all I had to do was:
yy at the chapter folded line
:e nameofchapter.tex
p

but when going back to the Thesis.tex file it wouldn't paste anything yanked from another file.

Solution? Using named buffers, like so:

:210,225ya b
This yanks lines 210-225 to buffer named b
then in the other file:
"bp
This pastes buffer b

Thanks to this site which had the syntax for line addresses for this operation, in other docs like my vi book I could only find things that worked for the current line or for a few lines only (like "byy or "b5yy)