Coding pink noise

[Amphiprion]

OK, I thought this would be a simple operation like filtering an audio file, but apparently it's not. I'm trying to generate band-limited pink noise (20-100Hz) in Matlab from white gaussian noise. I could be lazy and just import and filter a wav file of pink noise, but I'm trying to do this and learn something at the same time.

Question: has anyone done this? The easiest algorithms I can find are pseudocode such as this:

white=(whichever method you choose);
buf0=0.997 * buf0 + 0.029591 * white;
buf1=0.985 * buf1 + 0.032534 * white;
buf2=0.950 * buf2 + 0.048056 * white;
buf3=0.850 * buf3 + 0.090579 * white;
buf4=0.620 * buf4 + 0.108990 * white;
buf5=0.250 * buf5 + 0.255784 * white;
pink=buf0 + buf1 + buf2 + buf3 + buf4 + buf5;

and

b0 = 0.99886 * b0 + white * 0.0555179;
b1 = 0.99332 * b1 + white * 0.0750759;
b2 = 0.96900 * b2 + white * 0.1538520;
b3 = 0.86650 * b3 + white * 0.3104856;
b4 = 0.55000 * b4 + white * 0.5329522;
b5 = -0.7616 * b5 - white * 0.0168980;
pink = b0 + b1 + b2 + b3 + b4 + b5 + b6 + white * 0.5362;
b6 = white * 0.115926;

I'm pretty sure the last two lines of the second example are transposed, but that's how it was written on the website I pulled it from. Anyway, I'm trying to figure out how the coefficients affect the pink noise output, and how to generate them. The second example is supposed to be accurate down to 9.2Hz (+/-.05db) at 44.1kHz, but I have no idea why, how to calculate this, or how to verify this. Any DSP folk that have any idea how to do this? I'm regretting selling my textbooks back.

[Amphiprion]

Nevermind, it helps to read further down the page, dur. If anyone wants to know, they're just combinations of hand-tweaked 6db/octave lowpass filters used to approximate a 3dB/octave low pass response for the pink noise. See pic:

http://www.firstpr.com.au/dsp/pink-noise/pinkknee.gif