From Wikipedia we can refer all the topics. The volunteers from many parts of the
world provided the topics
in different ares. It is updated frequently , and the old information got removed to accomodate the New one.
Other things are also available like Frequently asked Questions,advice fro parents , where to ask questions some links provide much information. It is available in different lanugages. It has more and more articles in English itself.
If you put a google search , the first thing you will get is a link to this
wikipedia.The history tells that it was established in Nupedia . Wikipedia has advantages over traditional paper encyclopedias. Wikipedia has a very low "publishing" cost for adding or expanding entries and a low environmental impact, since it need never be printed.
Wikipedia uses a simple yet powerful page layout to allow editors to concentrate on adding material rather than page design. These include automatic sections and subsections, automatic references and cross-references, image and table inclusion, indented and listed text, links ISBNs and math, as well as usual formatting elements and most world alphabets and common symbols. Most of these have simple formats that are deliberately very easy and intuitive.
So this is the best website to refer