In 1855 he removed to Chicago, served for three years as bookkeeper in a planing-mill, and in 1858 entered the banking house of the Merchant's Loan and Trust Company, of which he was cashier in 1861-1868.
I have a bookkeeper.
The bookkeeper's name and number are in the top right drawer of my desk.
Frank Robinson, Pemberton's bookkeeper, named the drink Coca Cola and with his unique script handwriting wrote out that name.
Secondly, you will want the letter to come from someone official - a pastor, the church bookkeeper, an elder - someone who is informed as to what is going on in the church and gives their full blessing to seek funds for the need.