static public void printCoauthorTable() {
        Iterator it = Person.iterator();
        int coauthors[] = new int[501];
        Person pers;
        int c;
        
        while (it.hasNext()) {
            pers = (Person) it.next();
            c = pers.getNumberOfCoauthors();
            if (c > 500)
                c = 500;
            coauthors[c]++;
        }
        System.out.println();
        System.out.println("person: coauthors");
        
        System.out.println("Number of coauthors: Number of persons");
        int n = 0;
        for (int j=0; j <= 500; j++) {
            if (coauthors[j] == 0)
                continue;
            n++;
            System.out.print(j + ": " + coauthors[j]+ "  ");
            if (n%5 == 0)
                System.out.println();
        }
        System.out.println();      
    }