diff --git a/tutorials/custom_language_support/lexer_and_parser_definition.md b/tutorials/custom_language_support/lexer_and_parser_definition.md
index bf061bc4c..52e528b65 100644
--- a/tutorials/custom_language_support/lexer_and_parser_definition.md
+++ b/tutorials/custom_language_support/lexer_and_parser_definition.md
@@ -4,7 +4,7 @@ title: 4. Lexer and Parser Definition
 <!-- Copyright 2000-2020 JetBrains s.r.o. and other contributors. Use of this source code is governed by the Apache 2.0 license that can be found in the LICENSE file. -->
 
 The lexical analyzer defines how the [contents of a file are broken into tokens](/reference_guide/custom_language_support/implementing_lexer.md), which is the basis for supporting custom language features.
-The easiest way to create a lexer is to use [JFlex](https://jflex.de/)
+The easiest way to create a lexer is to use [JFlex](https://jflex.de/).
 
 * bullet item
 {:toc}