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| English | Russian |
| appreciation letter | благодарственное письмо (ВосьМой) |
| confirmation letter | письменное подтверждение ("A confirmation letter is correspondence that is sent to confirm an oral agreement. It can be business or personally related. The letter can also confirm a reservation, a response to an invitation, receipt of a various items or services, or meeting and conference arrangements."  wikihow.com ART Vancouver) |