3dB and 6dB Per Octave Rolloff Digital Filters / Generating Pink and Brown Noise So I would like to have a design method for filters with 3dB and 6dB per octave roll off -- for generating pink and brown noise respectively. 

I know the following 'pinking' filters exist:
Filter to add 3dB per octave?

But the poster says he doesn't remember the value for A, nor does he give any idea of how he did it in the first place. 

So my main question is:

How do we pick the poles and zeros of such a filter?
-6 dB / octave is trivial.

a common reference for a pinking filter is http://www.firstpr.com.au/dsp/pink-noise/