To add on top of that: In germany it's even impossible to sell the full copyright (Urheberrechte). You can waive some (the right to be named as the author) and you can sell the rights to use the work (Verwertungsrechte) but some others can not be transferred.
For example the right, that the work may not be used to defame the author and may not be used in such contexts. The term copyright translates very badly to German law. (Sorry, on a mobile connection, so just one short example)
