diff --git a/src/library/library.jsx b/src/library/library.jsx
index a840e4e..b386d9f 100644
--- a/src/library/library.jsx
+++ b/src/library/library.jsx
@@ -10,7 +10,7 @@ const Library = () => {
   return (
     <>
       <SoftAd href="https://alexbainter.gumroad.com/l/generative-music-systems">
-        "Building Generative Music Systems" course available now
+        &ldquo;Building Generative Music Systems&rdquo; course available now
       </SoftAd>
       <Category
         title={'Recently played'}
diff --git a/src/soft-ad/soft-ad.jsx b/src/soft-ad/soft-ad.jsx
index 64de4f6..844a0ba 100644
--- a/src/soft-ad/soft-ad.jsx
+++ b/src/soft-ad/soft-ad.jsx
@@ -1,4 +1,5 @@
 import React from 'react';
+import propTypes from 'prop-types';
 import styles from './soft-ad.module.scss';
 
 const SoftAd = ({ children, href }) => {
@@ -14,4 +15,9 @@ const SoftAd = ({ children, href }) => {
   );
 };
 
+SoftAd.propTypes = {
+  children: propTypes.node.isRequired,
+  href: propTypes.string.isRequired,
+};
+
 export default SoftAd;