Different Copyrights for Mozart String quartet

[cellofeel]

Hi
do you know why there is 2 differents copyright for the strings quartet of mozart
example: http://imslp.org/wiki/String_Quartet_No ... Amadeus%29
- the score file is PD in europe,
- the parts files are only USA PD
But it seem that the publisher is exactly the same when you look at the sheet music.

Thank you

[carmar1791]

Every Country has it's laws.
The score is the same but laws are different in each region.
See here for public domain laws :
http://imslp.org/wiki/Public_domain

Greetings
Carmar