diff --git a/LICENSE b/LICENSE
index d6d49386..9efb0660 100644
--- a/LICENSE
+++ b/LICENSE
@@ -1,6 +1,6 @@
 MIT License
 
-Copyright (c) 2020-2021 Masashi SHIBATA
+Copyright (c) 2020-2023 Masashi SHIBATA
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal
@@ -19,3 +19,28 @@ AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 SOFTWARE.
+
+-----------------------------------------------------------------------------
+
+Optuna Dashboard contains the codes from SQLAlchemy project.
+
+Copyright 2005-2019 SQLAlchemy authors and contributors <see AUTHORS file>.
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of
+this software and associated documentation files (the "Software"), to deal in
+the Software without restriction, including without limitation the rights to
+use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
+of the Software, and to permit persons to whom the Software is furnished to do
+so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.
+
diff --git a/docs/index.rst b/docs/index.rst
index ac8b7e6a..6c73d251 100644
--- a/docs/index.rst
+++ b/docs/index.rst
@@ -17,6 +17,11 @@ Real-time dashboard for `Optuna <https://github.com/optuna/optuna>`_.
    errors
    tutorials/index
 
+LICENSE
+=======
+
+This software is licensed under the MIT license and uses the codes from SQLAlchemy (MIT) project,
+see `LICENSE <https://github.com/optuna/optuna-dashboard/blob/main/LICENSE>`_ for more information.
 
 Links
 =====
diff --git a/optuna_dashboard/_storage_url.py b/optuna_dashboard/_storage_url.py
index f67623c7..8f1bb1fb 100644
--- a/optuna_dashboard/_storage_url.py
+++ b/optuna_dashboard/_storage_url.py
@@ -17,6 +17,8 @@ if TYPE_CHECKING:
     from optuna.storages import JournalStorage
 
 
+# The code to declare `rfc1738_pattern` variable is quoted from the source code
+# of SQLAlchemy project (MIT License). See LICENSE file for detials.
 # https://github.com/zzzeek/sqlalchemy/blob/c6554ac52/lib/sqlalchemy/engine/url.py#L234-L292
 rfc1738_pattern = re.compile(
     r"""