Stability of Lagarrange points

[E92M3]

I was reading this on wiki:
http://en.wikipedia.org/wiki/Lagrangian_point

In the stability section, it claimed that for L4 and L5 to be stable the following must hold:

\frac{M_1}{M_2}\geq24.96

Why is this the case? Where can I find proof?

[ideasrule]

That claim has a citation:

http://wmap.gsfc.nasa.gov/media/ContentMedia/lagrange.pdf

where you'll find the complete proof