Here is the article below:
The importance of the Abhidhamma Pitaka in classical Sinhalese Buddhism is suggested by the fact that it came to be furnished, not only, like much of the canon, with a commentary and a subcommentary on that commentary, but even with a subsubcommentary on that subcommentary.On the other hand, this relentless sub-commenting might be illustrative of what has been called "Shastra-vasna" or The Lust for Scriptures rather than a true effort at Nirvana , as envisioned by the Buddha. In more recent centuries, Burma has become the main centre of abhidhamma studies.
http://en.wikipedia.org/wiki/Abhidhamma

