Instruction: Parse the product information to locate the target attribute, and then provide the extracted value of the target attribute and its source in the output, specifying None if the attribute is not present.

Input:
Product title: Evga Geforce Gt 640 Graphic Card . 901 Mhz Core . 2 Gb Ddr3 Sdram . Pci Express 3.0 X16 . 1782 Mhz Memory Clock . 2560 X 1600 . Fan Cooler . Directx 11.0, Directcompute 5.0, Opengl 4.2, Opencl . Hdmi . Dvi "Product Type: Video Cards/Graphic Cards"
Product description: EVGA GeForce GT 640 Graphic Card - 901 MHz Core - 2 GB DDR3 SDRAM - PCI Express 3.0 x16 EVGA GeForce GT 640 Graphic Card - 901 MHz Core - 2 GB DDR3 SDRAM - PCI Express 3.0 x16 - 1782 MHz Memory Clock - 2560 x 1600 - Fan Cooler - DirectX 11.0, DirectCompute 5.0, OpenGL 4.2, OpenCL - HDMI - DVI GEFORCE GT 640 2048MB GeForce GT 640 (Dual Slot) 1 x DVI to VGA Adapter (For DVI-I) Disc User Guide PRODUCT TYPE/ CATEGORY: Graphic Card PART# = 02G-P4-2643-KR Manufacturer Warranty: 3 Year
Product feature: Video Cards, Graphic Cards
Product brand: OEM
Target attributes: Interface
Answer: attribute: interface
value: pci express
source: product title
attribute: interface
value: pci express
source: product description