Literal constants may be written by using an external representation of the data. In general, the external representation must be quoted (see Quoting); but some external representations can be used without quotation.
"abc" => "abc" 145932 => 145932 #t => #t #\a => #\a
The external representation of numeric constants, string constants, character constants, and boolean constants evaluate to the constants themselves. Symbols, pairs, lists, and vectors require quoting.