diff --git a/docs/api/utils.rst b/docs/api/utils.rst
deleted file mode 100644
index 38ea3b70..00000000
--- a/docs/api/utils.rst
+++ /dev/null
@@ -1,5 +0,0 @@
-``dependency_injector.utils``
------------------------------
-
-.. automodule:: dependency_injector.utils
-   :members:
diff --git a/docs/examples/index.rst b/docs/examples/index.rst
index 89d623fb..3d57076e 100644
--- a/docs/examples/index.rst
+++ b/docs/examples/index.rst
@@ -16,3 +16,4 @@ and powered by *Dependency Injector* framework.
     :maxdepth: 2
 
     movie_lister
+    services_miniapp
diff --git a/docs/examples/services_miniapp.rst b/docs/examples/services_miniapp.rst
new file mode 100644
index 00000000..33ea11ac
--- /dev/null
+++ b/docs/examples/services_miniapp.rst
@@ -0,0 +1,73 @@
+Services mini application example
+---------------------------------
+
+.. meta::
+   :description: "Services miniapp" is an example mini application that 
+                 consists from several services that have dependencies on 
+                 some standard and 3rd-party libraries for logging, 
+                 interaction with database and remote service via API. 
+                 "Services miniapp" example demonstrates usage of 
+                 Dependency Injector for creating several IoC containers.
+
+"Services miniapp" is an example mini application that consists from several 
+services that have dependencies on some standard and 3rd-party libraries for 
+logging, interaction with database and remote service calls via API.
+
+"Services miniapp" example demonstrates usage of 
+:doc:`Dependency Injector <../index>` for creating several IoC containers.
+
+Instructions for running:
+
+.. code-block:: bash
+
+    python run.py 1 secret photo.jpg
+
+Example application
+~~~~~~~~~~~~~~~~~~~
+
+Classes diagram:
+
+.. image:: /images/miniapps/services/classes.png
+    :width: 100%
+    :align: center
+
+
+Example application structure:
+
+.. code-block:: bash
+
+    /example
+        /__init__.py
+        /main.py
+        /services.py
+
+
+Listing of ``example/services.py``:
+
+.. literalinclude:: ../../examples/miniapps/services/example/services.py
+   :language: python
+   :linenos:
+
+Listing of ``example/main.py``:
+
+.. literalinclude:: ../../examples/miniapps/services/example/main.py
+   :language: python
+   :linenos:
+
+IoC containers
+~~~~~~~~~~~~~~
+
+Listing of ``containers.py``:
+
+.. literalinclude:: ../../examples/miniapps/services/containers.py
+   :language: python
+   :linenos:
+
+Run application
+~~~~~~~~~~~~~~~
+
+Listing of ``run.py``:
+
+.. literalinclude:: ../../examples/miniapps/services/run.py
+   :language: python
+   :linenos:
diff --git a/docs/images/miniapps/services/classes.png b/docs/images/miniapps/services/classes.png
new file mode 100644
index 00000000..8e9d29f7
Binary files /dev/null and b/docs/images/miniapps/services/classes.png differ
diff --git a/docs/main/changelog.rst b/docs/main/changelog.rst
index 27289641..a7da69e6 100644
--- a/docs/main/changelog.rst
+++ b/docs/main/changelog.rst
@@ -11,6 +11,11 @@ Development version
 -------------------
 - No features.
 
+3.1.0
+-----
+- Add "Services mini application" example.
+- Fix minor error in ``Factory`` provider API doc.
+
 3.0.1
 -----
 - Add ``*.c`` source files under version control.
diff --git a/examples/miniapps/services/example/main.py b/examples/miniapps/services/example/main.py
index d3399ff7..f1386c1a 100644
--- a/examples/miniapps/services/example/main.py
+++ b/examples/miniapps/services/example/main.py
@@ -2,7 +2,26 @@
 
 
 def main(uid, password, photo, users_service, auth_service, photos_service):
-    """Example main function."""
+    """Authenticate user and upload photo.
+
+    :param uid: User identifier.
+    :type uid: int
+
+    :param password: User's password for verification.
+    :type password: str
+
+    :param photo_path: Path to photo for uploading.
+    :type photo_path: str
+
+    :param users_service: Users service.
+    :type users_service: example.services.UsersService
+
+    :param auth_service: Authentication service.
+    :type auth_service: example.services.AuthService
+
+    :param photo_service: Photo service.
+    :type photo_service: example.services.PhotoService
+    """
     user = users_service.get_user_by_id(uid)
     auth_service.authenticate(user, password)
     photos_service.upload_photo(user['uid'], photo)
diff --git a/examples/miniapps/services/example/services.py b/examples/miniapps/services/example/services.py
index e907c1ca..4344e003 100644
--- a/examples/miniapps/services/example/services.py
+++ b/examples/miniapps/services/example/services.py
@@ -1,47 +1,103 @@
 """Example business services module."""
 
 
-class UsersService(object):
+class BaseService(object):
+    """Service base class."""
+
+
+class UsersService(BaseService):
     """Users service."""
 
     def __init__(self, logger, db):
-        """Initializer."""
+        """Initializer.
+
+        :param logger: Logger instance.
+        :type logger: logging.Logger
+
+        :param db: Database connection.
+        :type db: sqlite3.Connection
+        """
         self.logger = logger
         self.db = db
 
     def get_user_by_id(self, uid):
-        """Return user's information by login."""
+        """Return user's data by identifier.
+
+        :param uid: User identifier.
+        :type uid: int
+
+        :rtype: dict
+        """
         self.logger.debug('User %s has been found in database', uid)
-        return {'uid': uid,
-                'password_hash': 'secret_hash'}
+        return dict(uid=uid, password_hash='secret_hash')
 
 
-class AuthService(object):
-    """Auth service."""
+class AuthService(BaseService):
+    """Authentication service."""
 
     def __init__(self, logger, db, token_ttl):
-        """Initializer."""
+        """Initializer.
+
+        :param logger: Logger instance.
+        :type logger: logging.Logger
+
+        :param db: Database connection.
+        :type db: sqlite3.Connection
+
+        :param token_ttl: Token lifetime in seconds.
+        :type token_ttl: int
+        """
         self.logger = logger
         self.db = db
         self.token_ttl = token_ttl
 
     def authenticate(self, user, password):
-        """Authenticate user."""
+        """Authenticate user.
+
+        :param user: User's data.
+        :type user: dict
+
+        :param password: User's password for verification.
+        :type password: str
+
+        :raises: AssertionError when password is wrong
+
+        :rtype: None
+        """
         assert user['password_hash'] == '_'.join((password, 'hash'))
         self.logger.debug('User %s has been successfully authenticated',
                           user['uid'])
 
 
-class PhotosService(object):
+class PhotosService(BaseService):
     """Photos service."""
 
     def __init__(self, logger, db, s3):
-        """Initializer."""
+        """Initializer.
+
+        :param logger: Logger instance.
+        :type logger: logging.Logger
+
+        :param db: Database connection.
+        :type db: sqlite3.Connection
+
+        :param s3: AWS S3 client.
+        :type s3: boto.s3.connection.S3Connection
+        """
         self.logger = logger
         self.db = db
         self.s3 = s3
 
     def upload_photo(self, uid, photo_path):
-        """Upload user photo."""
+        """Upload user photo.
+
+        :param uid: User identifier.
+        :type uid: int
+
+        :param photo_path: Path to photo for uploading.
+        :type photo_path: str
+
+        :rtpe: None
+        """
         self.logger.debug('Photo %s has been successfully uploaded by user %s',
                           photo_path, uid)
diff --git a/src/dependency_injector/__init__.py b/src/dependency_injector/__init__.py
index 169c3ea7..a344b9bf 100644
--- a/src/dependency_injector/__init__.py
+++ b/src/dependency_injector/__init__.py
@@ -1,6 +1,6 @@
 """Dependency injector top-level package."""
 
-VERSION = '3.0.1'
+VERSION = '3.1.0'
 """Version number that follows semantic versioning.
 
 :type: str