diff --git a/src/internal/core/index.ts b/src/internal/core/index.ts
index 0a5bec1..3c5c0eb 100644
--- a/src/internal/core/index.ts
+++ b/src/internal/core/index.ts
@@ -316,7 +316,7 @@ export function notMatch(parser: Parser<unknown>): Parser<null> {
  * @returns A {@link Failure} object if `parserExcluded` succeeds, or if `parserIncluded` fails, and a {@link Success} object 
  * 			otherwise.
  */
-export function difference(parserIncluded: Parser<unknown>, parserExcluded: Parser<unknown>): Parser<string> {
+export function difference(parserIncluded: Parser<string>, parserExcluded: Parser<string>): Parser<string> {
 	return new Parser((input, index, state) => {
 		const exclude = parserExcluded.handler(input, index, state);