I'm just able to read the reference about the libraries but not seeing any LINK from where i can download the libraries
Most libraries are written by third parties so are not downloadable from the arduino.cc site directly.
A quick google search will give you what you want.
Mowcius
Some of the 'official libraries' can be found on this Arduino.cc page:
Many others in the Arduino playground pages:
http://www.arduino.cc/playground/
Lefty