Granted, I have not taken the effort to translate 
the page, but they look like they are studio 
photocopies (not meant as a bad thing).  The kind 
that a couple of sets of copies are made and then 
given out to the head animators to use as 
references so the characters will looks the same 
throughout the series/episode.
Also, just because something may be a photocopy 
does not meant that is common and not worth 
anything, or even bad to have.  Furthermore, from 
what I have seen these types of photocopy 
sketches often have hand written notes and 
comments on them by the artists and staff.