../ fig1.gif 30-Mar-1997 22:27 31342 fig2.gif 30-Mar-1997 22:27 29270 fig3.gif 30-Mar-1997 22:27 40811 fig4.gif 30-Mar-1997 22:27 29414 fig5.gif 30-Mar-1997 22:27 32637 fig6.gif 30-Mar-1997 22:27 43033 fig7.gif 30-Mar-1997 22:27 37622