@Test
public void unknownRange() {

    PageRange pr = PageParser.parse("??-??");
    assertEquals("??-??", pr.getLiteral());
    assertEquals("??", pr.getPageFirst());
    assertNull(pr.getNumberOfPages());
    assertTrue(pr.isMultiplePages());
    pr = PageParser.parse("?? - ??");
    assertEquals("?? - ??", pr.getLiteral());
    assertEquals("??", pr.getPageFirst());
    assertNull(pr.getNumberOfPages());
    assertTrue(pr.isMultiplePages());
}