public void printOwnerships() {
                Set<Author> authorSet = ownerships.keySet();
                
                Iterator<Author> authorIter = authorSet.iterator();
                while(authorIter.hasNext()) {
                        Author author = authorIter.next();
                        System.out.println("Author Name: " + author.getAuthorName() + ", Ownership size: " + ownerships.get(author) + ".");
                }
        }