One to Many relationship [on hold]

Suppose I have “one to many” relationship between 2 classes: library and book (a library have one or many books)

Is it correct if I expressed it in this way :

class Library {     List<book> books;     //... }  class Book {     Library library     //... } 

I mean that is it correct if I translated the relation into both classes? Or must I choose: either I give the library class a reference to their books or I give the book the reference to its library?