The entries starting with Scarborough, Yatesburg, and Robinson are books.
They all have publishing companies.
The first is from a periodical. The 19.2 tells you the issue. The ones with Web are from the internet.
I think the single sentence that shows it is a personal letter is "that all I can say is that I am well" as the rest of the letter is details about his military campaign so could be part of a more formal memo if it were not for this opening sentence so that seems to be how to identify it as such.
Keeping? If it is suppose to be negative
