diff --git a/Markdown Item URI with Citekey.js b/Markdown Item URI with Citekey.js
index 6673230..0a85380 100644
--- a/Markdown Item URI with Citekey.js	
+++ b/Markdown Item URI with Citekey.js	
@@ -8,7 +8,7 @@
     "maxVersion":"",
     "priority":200,
     "inRepository":false,
-    "lastUpdated":"2020-10-14"
+    "lastUpdated":"2020-11-30"
     }
      
     
@@ -20,7 +20,7 @@
         
                 var year = date && !isNaN(date) ? date + ". " : (typeof item.date == 'undefined'?  "" : item.date + ". ");
                 var library_id = item.libraryID ? item.libraryID : "";
-                var author_lastname = item.creators[0].lastName ? item.creators[0].lastName + ". " : "";
+                var author_lastname = getValidAuthor(item);
                 var title = item.title ? "*" + item.title + "*" : "";
                 var key = item.key;
                 var citekey = item.citationKey ? `[[${item.citationKey}]]` : "";
@@ -28,3 +28,12 @@
                 Zotero.write(`[${author_lastname}${year}${title}](zotero://select/items/${library_id}_${key})${citekey}`);
             }
         }
+
+        function getValidAuthor(item){
+            if(item.creators && item.creators[0] && item.creators[0].lastName){
+                return item.creators[0].lastName + ". ";
+            }else{
+                return "";
+            }
+    
+        }
diff --git a/Markdown Item URI.js b/Markdown Item URI.js
index 21c0880..55144fb 100644
--- a/Markdown Item URI.js	
+++ b/Markdown Item URI.js	
@@ -8,7 +8,7 @@
 	"maxVersion":"",
 	"priority":200,
 	"inRepository":false,
-	"lastUpdated":"2020-10-15"
+	"lastUpdated":"2020-11-30"
 	}
 	 
 	
@@ -16,14 +16,23 @@
 		var item;
 		while(item = Zotero.nextItem()) {
 			var date = Zotero.Utilities.strToDate(item.date).year;
-	
+
 			var year = date && !isNaN(date) ? date + ". " : (typeof item.date == 'undefined'?  "" : item.date + ". ");
 			var library_id = item.libraryID ? item.libraryID : "";
-			var author_lastname = item.creators[0].lastName ? item.creators[0].lastName + ". " : "";
+			var author_lastname = getValidAuthor(item);
 			var title = item.title ? "*" + item.title + "*" : "";
 			var key = item.key;
 	
 			Zotero.write(`[${author_lastname}${year}${title}](zotero://select/items/${library_id}_${key})`);
 		}
 	}
+
+	function getValidAuthor(item){
+		if(item.creators && item.creators[0] && item.creators[0].lastName){
+			return item.creators[0].lastName + ". ";
+		}else{
+			return "";
+		}
+
+	}