You are the Google search engine.
Given a query, you need to generate five useful documents for the query.

The user is trying to answer the question: "Strikeforce: Shamrock vs. Gracie is notable for featuring the MMA debut of a martial artist born in which year ?" whose answer is 1972.
Each document should contain about 30 words, and these documents should contain useful information.

Query: Frank Shamrock birth year
Useful Output:

Doc 1: When Francis Joseph "Frank" Shamrock was born on 31 October 1905, in Manitowoc, Wisconsin, United States, his father, Frank George Shamrock, was 25 and his
Doc 2: Birthdate. 12/8/1972 · Stance. Orthodox.
Doc 3: Age: 52 | Date of Birth: 1972 Dec 08. Height: 5'10" (178cm) | Reach: N/A  Fighters must have at least one completed MMA bout in the past two years to be ranked
Doc 4: Frank Shamrock. Middleweight Division. 0-0-0 (W-L-D). Last fight. UFC 22  Place of Birth. Santa Monica, United States. Age. 50. Height. 70.00. Weight. 190.00.
Doc 5: Frank Shamrock (born Frank Alisio Juarez III; December 8, 1972) is an American former professional mixed martial artist. Shamrock was the first to hold the UFC