how to match n- lists for a common elements.

[Grzegorz Ślusarek]

Hi all. I my application i have situation when i have some lists and i 
must get from lists common elements. Exacly i don't know how many list I 
  have so at the moment of creation each of one I append them to one 
list. So I get list wchich consist of lists of objects. And now i want 
to get common objects of this list. How to do it?
Grzegorz