Ostrogradski’s theorem's proof

[MathematicalPhysicist]

I am looking for a proof of the next theorem:

"If the higher order time derivative Lagrangian is non-degenerate, there is at least one linear instability in the Hamiltonian of this system."

Where Non-degeneracy means that the highest time derivative term can be expressed in terms of canonical variables.

P.S
I prefer a reference, as in a book or article.

 

[vanhees71]

Where did you get the theorem from? I've never heard of it.

 

[MathematicalPhysicist]

Here:
http://arxiv.org/pdf/1209.0583v4.pdf

The first pages.