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: "How did Russian composer, Pyotr Ilyich Tchaikovsky describe Karl Davydov?" whose answer is czar of cellists.
Each document should contain about 30 words, and these documents should contain useful information.

Query: Tchaikovsky letters to Karl Davydov
Useful Output:

Doc 1: Correspondence with Tchaikovsky. 13 letters from Tchaikovsky to Karl Davydov have survived, dating from 1872 to 1886, all of which have been
Doc 2: Instead with Vladimir Davydov (aka. Bob), the composer's nephew. Love letters published in English for the first time in 2018 also show a secret
Doc 3: ↑ In January 1880, Tchaikovsky received a commission from Karl Davydov, the director of the Saint Petersburg Conservatory, to provide some music
Doc 4: In December, he wrote to his favorite nephew, Vladimir “Bob” Davydov:  Surviving letters and memoirs from friends and family who actually knew
Doc 5: In this paper, I will argue that Tchaikovsky's musical developments grew because of his relationships with his family, friends, and colleagues