The link http://www.dtic.mil/dtic/tr/fulltext/u2/a351960.pdf for the paper of [Sadler and Swami](http://www.dtic.mil/dtic/tr/fulltext/u2/a351960.pdf) is broken. The proper link is: https://apps.dtic.mil/sti/pdfs/ADA351960.pdf
The link http://www.dtic.mil/dtic/tr/fulltext/u2/a351960.pdf for the paper of Sadler and Swami is broken.
The proper link is:
https://apps.dtic.mil/sti/pdfs/ADA351960.pdf