Dr. Andrew B. Chung, MD/PhD wrote:

> Word spreads fast on the Internet. And there are those who feign
> disbelief at the estimate than more than 90,000 people are using the
> 2PD Approach, which has been published on the Internet since 1998.

I use 4PD Approach and it works well with me.

Hope the above information enlightens you.

--
Juhana