Instruction: Using the product's title, description, features, price, and brand, identify and retrieve the values associated with a specified set of target attributes. Output the extracted values along with their respective sources (e.g., title or feature) indicating where each value was found.

Input:
Product title: ELK 66234-1-LA, Barton Round Glass Semi Flush Ceiling Lighting, 1 Light, Polished Nickel
Product description: The ELK 66234-1-LA Barton collection Close to Ceiling Lighting in Polished Nickel uses Incandescent light output and brings Antique style. The total wattage is 75 and the voltage is 120 volts. The ELK Lighting 66234-1-LA requires 1 bulb (not included). Additional Information: Shade-White Hand-Blown Glass - Type 3.
Product feature: Requires: (1) - 53W A19, E26 Med Soft 1000Hr 1100LM 120V Halogen Light Bulb Light Bulb, White Hand-Blown Glass - Type 3
Product brand: ELK
Target attributes: Shade Material
Answer: attribute: shade material
value: glass
source: product feature
attribute: shade material
value: glass
source: product title
attribute: shade material
value: glass
source: product description