Neither of your sources discusses stealth detection. I’ve read a bit on low freq stuff, but it is inherently innaccurate. Anything else? Google mostly returns blogs.
Read a bit about PCL (passive coherent location) techniques.
http://www.motherjones.com/news/feature/2000/01/stealth.html
Has, inpart, this:
The most fundamental problem, however, is that stealth planes are hardly undetectable to enemy defenses. The B-2 is nearly as visible as a 747 to a ground observer, one reason that it — like the F-117 — flies only at night. Furthermore, the Pentagon’s supposedly invisible stealth aircraft fly into action with the same radar-jamming escort planes that accompany conventional warplanes. Demand for jammers was so high during the Kosovo conflict that the Pentagon had to redeploy electronic warfare planes from Turkey, where they are being used in the ongoing air campaign against Iraq. “For stealth planes, jammers are just like American Express,” says a military analyst who works with Congress. “Don’t leave home without them.”
and this -
It’s impossible to know just how stealthy stealth planes really are since the Pentagon has made the entire program highly classified, which means that it operates virtually without oversight from Congress or watchdog groups. There are, however, disturbing signs that stealth planes are far from invulnerable.
During the Gulf War, the British Royal Navy infuriated the Pentagon by announcing that it had detected F-117 stealth fighters from 40 miles away with 1960s-era radar.
The Iraqis used antiquated French radar during that conflict, and they, too, claimed to have detected F-117s. The General Accounting Office, Congress’ watchdog agency, tried to verify the Iraqi claim, but the Pentagon refused to turn over relevant data to GAO investigators. Likewise, the Pentagon has revealed no specific details about the F-117 shot down over Kosovo, but Yugoslav sources and news accounts say the Serbs brought the plane down with a Russian SA-3 missile, a 35-year-old model. General McPeak calls the incident a “lucky shot.”
And a good discussion if you haven’t spent some time her
http://en.wikipedia.org/wiki/Stealth_aircraft (L band detection is mentioned)