public String getUpperLimit()
    {
        String retval = null;
        COSArray arr = node.getCOSArray(COSName.LIMITS);
        if( arr != null )
        {
            retval = arr.getString( 1 );
        }
        return retval;
    }
@Test
    void testUpperLimit() throws IOException
    {
        assertEquals("Astatine", this.node5.getUpperLimit());
        assertEquals("Astatine", this.node2.getUpperLimit());

        assertEquals("Zirconium", this.node24.getUpperLimit());
        assertEquals("Zirconium", this.node4.getUpperLimit());

        assertEquals(null, this.node1.getUpperLimit());
    }