diff --git a/resources/styles/main.scss b/resources/styles/main.scss
index fd9cf75..ded119f 100644
--- a/resources/styles/main.scss
+++ b/resources/styles/main.scss
@@ -40,6 +40,12 @@ body {
     flex: 1 1 auto;
   }
 
+  .attribution {
+    font-size: small;
+    color: $text-muted;
+    text-align: right;
+  }
+
   footer {
     @extend .flex;
     border-top: 2px solid black;
diff --git a/src/Provider/Dummy/DummyProvider.php b/src/Provider/Dummy/DummyProvider.php
index fa11cba..7e33693 100644
--- a/src/Provider/Dummy/DummyProvider.php
+++ b/src/Provider/Dummy/DummyProvider.php
@@ -37,18 +37,23 @@ class DummyProvider implements Provider
         throw new NotSupportedException();
     }
 
-    public function getName()
+    public function getName(): string
     {
         return "Dummy data for debugging";
     }
 
-    public function getShortName()
+    public function getShortName(): string
     {
         return "dummy";
     }
 
-    public function getIdentifier()
+    public function getIdentifier(): string
     {
         return "dummy";
     }
+
+    public function getAttribution(): ?string
+    {
+        return null;
+    }
 }
\ No newline at end of file
diff --git a/src/Provider/Provider.php b/src/Provider/Provider.php
index f7c1d85..d079c90 100644
--- a/src/Provider/Provider.php
+++ b/src/Provider/Provider.php
@@ -10,7 +10,8 @@ interface Provider
     public function getMessageRepository(): MessageRepository;
     public function getTrackRepository(): TrackRepository;
 
-    public function getName();
-    public function getShortName();
-    public function getIdentifier();
+    public function getName(): string;
+    public function getShortName(): string;
+    public function getIdentifier(): string;
+    public function getAttribution(): ?string;
 }
\ No newline at end of file
diff --git a/src/Provider/ZtmGdansk/ZtmGdanskProvider.php b/src/Provider/ZtmGdansk/ZtmGdanskProvider.php
index 84b660d..f3c2ce0 100644
--- a/src/Provider/ZtmGdansk/ZtmGdanskProvider.php
+++ b/src/Provider/ZtmGdansk/ZtmGdanskProvider.php
@@ -25,21 +25,26 @@ class ZtmGdanskProvider implements Provider
     private $tracks;
     private $messages;
 
-    public function getName()
+    public function getName(): string
     {
         return 'MZKZG - Trójmiasto';
     }
 
-    public function getShortName()
+    public function getShortName(): string
     {
         return 'Trójmiasto';
     }
 
-    public function getIdentifier()
+    public function getIdentifier(): string
     {
         return 'trojmiasto';
     }
 
+    public function getAttribution(): string
+    {
+        return '<a href="http://ztm.gda.pl/otwarty_ztm">Otwarte Dane</a> Zarządu Transportu Miejskiego w Gdańsku';
+    }
+
     public function __construct(
         EntityManagerInterface $em,
         GenericLineRepository $lines,
diff --git a/templates/app.html.twig b/templates/app.html.twig
index 6a80e47..5ed200f 100644
--- a/templates/app.html.twig
+++ b/templates/app.html.twig
@@ -29,6 +29,12 @@
                     </button>
                 </h2>
                 <departures :stops="stops" ref="departures" @update:state="departures.state = $event"></departures>
+                {% if provider.attribution %}
+                    <div class="attribution">
+                        <fa :icon="['fal', 'info-circle']"></fa>
+                        Pochodzenie danych: {{ provider.attribution|raw }}
+                    </div>
+                {% endif %}
             </section>
         </div>
         <div class="col-md-4 order-md-first">