i>
        <li><span style="font-family: ms sans serif;">Jacchia 77</span></li>
        <li><span style="font-family: ms sans serif;">LaFontaine-Hughes</span></li>
        <li><span style="font-family: ms sans serif;">Jacchia-Lineberry
(77 model)</span></li>
        <li><span style="font-family: ms sans serif;">MSIS-86 (C code)</span></li>
      </ul>
      <span style="font-family: ms sans serif;">All
these programs are
interchangeable, which means that any model, except MSIS, can be
easily chang