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: "who is the longest sitting supreme court justice?" whose answer is William O. Douglas.
Each document should contain about 30 words, and these documents should contain useful information.

Query: longest serving supreme court justice
Useful Output:

Doc 1: The Honourable Joseph P. Kennedy, the Supreme Court of Nova Scotia's longest serving Chief Justice, retires this week after more than four
Doc 2: At 99 years of age, Stevens was four years older than the previous justice to live longest, Stanley Reed, who was born in 1884, confirmed to the Court in 1938,
Doc 3: Associate Justice Clarence Thomas is the longest-serving of the justices, having sat on the Supreme Court for more than thirty years .
Doc 4: The longest serving justice was William O. Douglas, with a tenure of 13,358 days (36 years, 209 days). The longest serving chief justice was John Marshall, with
Doc 5: Justice William Douglas served the longest of the justices at over 36 years, or just over two years longer than both Stevens and Field. Others