• from 25 USD http://jakeofalltrades.wordpress.com/2007/09/30/25-head-mounted-display/#more-112
• or 250 USD http://www.i4u.com/article4612.html
• eMagin http://www.vrlogic.com/html/emagin.html
• Various http://www.yellomosquito.com/
• Comparison http://www.stereo3d.com/hmd.htm#chart

• http://www.eurekalert.org/pub_releases/2008-01/uow-clw011708.php

useful for mixed reality or virtual reality applications