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: Derek Heart Junior's Plus-Size Plaid Button-Front Blouse
Product description: Button down patch pocket with collar and roll back cuff
Product feature: 100% Cotton, Imported, Machine Wash, Plaid shirt with rolled short sleeves featuring spread collar and patch pockets at chest, Package Dimensions: 10.5 x 10 x 2 inches, Shipping Weight: 0.32 ounces, ASIN: B00US3VQLG, Item model number: AQXW905, Date first listed on Amazon: April 17, 2015, Average Customer Review: 4.0 out of 5 stars 1 customer review
Product brand: Derek Heart
Target attributes: Fastening Style
Answer: attribute: fastening style
value: button-front
source: product title