diff --git a/src/components/Articles/Categories/CategoryItem.js b/src/components/Articles/Categories/CategoryItem.js
index c997baf..0fa0291 100644
--- a/src/components/Articles/Categories/CategoryItem.js
+++ b/src/components/Articles/Categories/CategoryItem.js
@@ -1,4 +1,5 @@
 import React from 'react';
+import PropTypes from 'prop-types'
 import { useLocation } from '@reach/router'
 import { Link } from 'gatsby'
 import slugify from '../../../helpers/slugify'
@@ -14,3 +15,7 @@ const CategoryItem = ({ title }) => {
 
 export default CategoryItem
 
+CategoryItem.propTypes = {
+  title: PropTypes.string
+}
+
diff --git a/src/components/Articles/Search/Search.js b/src/components/Articles/Search/Search.js
index 07015f6..3a74707 100644
--- a/src/components/Articles/Search/Search.js
+++ b/src/components/Articles/Search/Search.js
@@ -1,4 +1,5 @@
 import React from 'react'
+import PropTypes from 'prop-types'
 
 const Search = ({ articlesLength }) => {
 	return (
@@ -9,4 +10,8 @@ const Search = ({ articlesLength }) => {
 	)
 }
 
-export default Search
\ No newline at end of file
+export default Search
+
+Search.propTypes = {
+	articlesLength: PropTypes.number
+}
\ No newline at end of file
diff --git a/src/components/Books/Books.js b/src/components/Books/Books.js
index 48b3b29..8b221ff 100644
--- a/src/components/Books/Books.js
+++ b/src/components/Books/Books.js
@@ -1,4 +1,5 @@
 import React from 'react';
+import PropTypes from 'prop-types'
 import slugify from '../../helpers/slugify'
 import Img from "gatsby-image"
 import './Books.scss'
@@ -17,4 +18,10 @@ const Books = ({ data: { edges } }) => {
   )
 }
 
-export default Books
\ No newline at end of file
+export default Books
+
+Books.propTypes = {
+  data: PropTypes.shape({
+    edges: PropTypes.array
+  })
+}
\ No newline at end of file
diff --git a/src/components/Offers/Books/BookItem.js b/src/components/Offers/Books/BookItem.js
index 2ae0529..e4621ba 100644
--- a/src/components/Offers/Books/BookItem.js
+++ b/src/components/Offers/Books/BookItem.js
@@ -1,4 +1,5 @@
 import React from 'react';
+import PropTypes from 'prop-types'
 import { Link } from 'gatsby'
 import slugify from '../../../helpers/slugify'
 
@@ -10,4 +11,8 @@ const BookItem = ({ title }) => {
   )
 }
 
-export default BookItem
\ No newline at end of file
+export default BookItem
+
+BookItem.propTypes = {
+  title: PropTypes.string
+}
\ No newline at end of file