diff --git a/CHANGELOG.md b/CHANGELOG.md
index 8797c84..8e77777 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,27 +1,3 @@
-# Changelog
-All notable changes to this project will be documented in this file.
-
-## [0.1.6] - 2020-07-22
-### Upgrade
-* Upgrade dependencies
-
-## [0.1.5] - 2020-05-30
+## [1.0.0] - 2020-08-26
 ### Added
-* Add coveralls and badge to README
-
-## [0.1.4] - 2020-05-29
-### Added
-* Fix usage example in README
-
-## [0.1.3] - 2020-05-29
-### Added
-* Fix install command on README
-
-## [0.1.2] - 2020-04-26
-### Added
-* CHANGELOG
-* MIT LICENSE
-
-## [0.1.0] - 2020-04-26
-### Added
-* Random generators for DNI, NIE and NIF.
\ No newline at end of file
+* ISBN util to validate and generate a valid random ISBN-10 or ISBN-13.
diff --git a/README.md b/README.md
index e9e9010..05c6491 100644
--- a/README.md
+++ b/README.md
@@ -3,7 +3,7 @@
 
 # ISBN Util
 
-This module check if an isbn is valid or not and also provide method to generate a valid random isbn (10 or 13)
+This module check if an ISBN is valid or not and also provide a method to generate a valid random ISBN-10 or ISBN-13
 
 ## Install
 
@@ -32,7 +32,3 @@ generate('10');
 //=> 'isbn-10: 8448122313'
 ```
 
-### Why this tool?
-
-// TBD
-
diff --git a/__test__/generator.test.js b/__test__/generator.test.js
index 9ec9a1f..e386f14 100644
--- a/__test__/generator.test.js
+++ b/__test__/generator.test.js
@@ -2,6 +2,11 @@ const generator = require('./../src/generator.js');
 const validator = require('./../src/validator.js');
 
 test('should return a valid isbn according with the passed param', () => {
-  const validIsbn = generator('10');
+  const validIsbn = generator('10').split(' ')[1];
   expect(validator(validIsbn)).toBe(true);
 });
+
+test('should return a string with the correct pattern depending on the type selected', () => {
+  expect(generator('10')).toContain('isbn-10: ');
+  expect(generator('13')).toContain('isbn-13: ');
+});
diff --git a/src/generator.js b/src/generator.js
index 2cba4aa..a5db780 100644
--- a/src/generator.js
+++ b/src/generator.js
@@ -8,7 +8,7 @@ const generator = (type = isbnTypes[10]) => {
   const randomNumber = parseInt(Math.random() * parseInt(Math.pow(10,type)));
   if ( type === isbnTypes[type] ) {
     const tempIsbn = randomNumber.toString();
-    return validator(tempIsbn) ? tempIsbn : generator(type);
+    return validator(tempIsbn) ? `isbn-${type}: ${tempIsbn}` : generator(type);
   } else {
     console.error('Invalid option. Pass "10" for isbn-10 and "13" for isbn-13');
     process.exit(1);