http://astrogeo.oxfordjournals.org/content/45/4/4.21.full may be this link little helpful for you 

Alternatively, you can look at

An Introduction to Waves and Oscillations in the Sun by Narayanan: 

http://www.springer.com/astronomy/astrophysics+and+astroparticles/book/978-1-4614-4399-5

or at:

Non-radial oscillations of stars by Unno et al.

http://www.tandfonline.com/doi/abs/10.1080/03091928008241176?journalCode=ggaf20#.VCP5P0QQauA

The latter is a bit old, but there have been several reprints and it gives a very good explanation of the theory of stellar pulsations in general.

You may find  by J. Harvey, "Sounding Out the Sun, Physics Today, October 1995, pages 32-38" to be a very good article on helio-seismology.

Essentially, in the case of the Sun (and other stars with a similar interior structure: basically a radiative core and a convective envelope) the oscillation normal modes are stocastically excited by the convection at the envelope of the star. The restoration force is the pressure in the p-modes. There are also other types of modes: the g-modes (whose restoration force is the gravity) are theoretically expected to propagate deep in star but there isn't yet an uncontroversial detection of them in the Sun due to the "noise" produced by convective features.

Take a look at the links at the Prof. Jørgen Christensen-Dalsgaard's web page.

http://users-phys.au.dk/jcd/

You can start with this:

http://astro.phys.au.dk/helio_outreach/english/engHA4.html

and then go through "The Bible":

http://astro.phys.au.dk/~jcd/oscilnotes/