How to format a sentence that a character has written down?

Question

I'm trying my hand at editing a friends work. They've written the following:

'Thinks he's the smartest one in the room,' Henry wrote on a piece of paper.

(For context, they use double quotation marks when they write dialogue.)

My instinct is that the single quotation marks are incorrect. I could be wrong.

I can think of two alternatives:

1. Double quotation marks:

   "Thinks he’s the smartest one in the room," Henry wrote on a piece of paper.

   I feel like the double quotation marks make it read too much like dialogue, however. Especially because there is a conversation happening around this line.

2. Italics:

   Thinks he's the smartest one in the room, Henry wrote on a piece of paper.

   A reason I lean towards this option is because "thinks he's the smartest one in the room" is a thought that Henry is having. (If Henry was simply thinking the phrase then I would use italics.)

So, am I supposed use single quotes, double quotes, or italics in this situation? Or something else? Or is it just a matter of style?

Answer 1

Marshal Plan has a great book named "The Marshall Plan for Novel Writing", Wherein he has recommended the use of ITALICS for the inner thoughts In inverted comas- referred to by you as double quotes. : http://www.dailywritingtips.com/dealing-with-a-characters-internal-thoughts/