modern portfolio theory - Typical risk aversion parameter value for mean-variance optimization?

What are typical values for risk aversion parameters $\lambda$ used in mean-variance optimization? Please provide references.

Just to be clear, I'm talking about the $\lambda$ in $U(w) = w'\mu - \frac{\lambda}{2} w' \Sigma w$, the utility function in mean-variance optimization.

Answer

Typical risk aversion levels lie between one and ten.

See pages 11f. in the following paper:
Preferences by Andrew Ang

EDIT: Unfortunately the paper doesn't seem to be available online anymore. The final source is the following book:

Asset Management: A Systematic Approach to Factor Investing (Financial Management Association Survey and Synthesis) 1st Edition by Andrew Ang

If you know a way to access the above chapter legally please let me know in the comments, I will update the post accordingly (I leave the original link for now).