relationelle vs. partitive nouns

hey

I'am doing an important asignment about post-head dependents, but a have some serious problems...

Can anyone explain the difference between ralationelle and patitive nouns???

I found 2 examples but unfortunately they dont make my any wiser...

father of the child (relationelle)

bottom of the list (partitive)

which would - author of the book- be ?

I belive that the head is author and the post-head dependent "of the book" is a complementation but I cant really explain why.?

- really hope someone will help me....