Instruction: Extract the value of the target attribute from the given product information and output it along with the corresponding source.

Input:
Product title: Sony VAIO E15 Series SVE15125CXS 15.5-Inch Laptop (Silver)
Product description: Accented with a diamond cut logo and aluminum lid, the VAIO E Series 15 laptop comes full of features like backlit keyboard, large clickable touchpad, and HD web camera. It comes with Sony Imagination Studio VAIO Edition, Sonys exclusive pre-installed software that allows you to create something worth sharing.
Product feature: Intel Core i5 3210M 2.5 GHz, 4 GB DDR3, 500 GB 5400 rpm Hard Drive, 15.5-Inch Screen, Windows 8
Product brand: Sony
Target attributes: Refresh Rate
Answer: attribute: refresh rate
value: None
source: None