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 author of book entitled principles of economics?" whose answer is Alfred Marshall.
Each document should contain about 30 words, and these documents should contain useful information.

Query: author of Principles of Economics
Useful Output:

Doc 1: Carsten Herrmann-Pillath and Christian Hederer provide creative synthesis out of the combination of domains that are hitherto conceived to be foreign. Now, the
Doc 2: Authors: Steven A. Greenlaw, David Shapiro, Daniel MacDonald; Publisher/website: OpenStax; Book title: Principles of Economics 3e; Publication
Doc 3: Principles of Economics by Alfred Marshall. Economic conditions are constantly changing, and each generation looks at its own problems in its own way.
Doc 4: Saifedean Ammous is an internationally best-selling author and economist. In 2018, Ammous authored The Bitcoin Standard: The Decentralized
Doc 5: Book Title: Principles of Economics. Author: [Author removed at request of original publisher]. Cover image for Principles of Economics.