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: "What type of "informal business group" is the Mitsubishi company considered to be an example of?" whose answer is keiretsu.
Each document should contain about 30 words, and these documents should contain useful information.

Query: what is an informal business group
Useful Output:

Doc 1: The informal organization is the aggregate of behaviors, interactions, norms, and personal/professional connections.
Doc 2: Informal groups are clusters of people who interact with each other for social or professional reasons, but are not part of the official
Doc 3: An informal group is a group of people who come together voluntarily and who are not formally felt by the firm. Informal groups can form around
Doc 4: Informal groups provide social status and satisfaction that may not be obtained from the formal organization.
Doc 5: Informal communication may result in informal groups ganging up together to resist official management decisions. In summary, this article