added sources to the engines

bib.bib

@@ -193,7 +193,7 @@
     year={2014}
 }
 
-@misc{UNITY_DOWNLOADS,
+@misc{UNITY_DOWNLOAD,
     title = {Unity herunterladen},
     author = {Unity},
     url = {https://unity3d.com/de/get-unity/download},
@@ -207,10 +207,87 @@
     author = {Unity},
 }
 
-@misc{WIKIPEDIA_2014,
+@misc{WIKIPEDIA_UNITY_GAME_LIST_2014,
     title = {List of Unity games},
     note = {lezter Zugriff am 7.2.2022},
     author = {Wikipedia},
     url = {https://en.wikipedia.org/wiki/List_of_Unity_games},
     year = {2014},
 }
+
+@misc{UNITY_PLATTFORMS,
+    title = { What platforms are supported by Unity? },
+    url = {https://support.unity.com/hc/en-us/articles/206336795-What-platforms-are-supported-by-Unity-},
+    author = {Jead},
+    year = {2022},
+    note = {letzer Zugriff 8.2.2022},
+}
+
+@misc{UNEAL_ENGINE_OWNER_2022,
+    title = {Who Owns Unreal Engine? – (2022)},
+    note = {letzer Zugriff 8.2.2022},
+    url = {https://www.gameplaydeveloper.com/who-owns-unreal-engine/},
+    year = {2022},
+}
+
+@misc{WIKIPEDIA_UNREAL_GAME_LIST,
+    title = {List of Unreal Engine games},
+    note = {letzer Zugriff 8.2.2022},
+    url = {https://en.wikipedia.org/wiki/List_of_Unreal_Engine_games},
+}
+
+@misc{UNREAL_ENGINE_PRICING_2022,
+    title = {LICENSING OPTIONS},
+    note = {letzer Zugriff 8.2.2022},
+    url = {https://www.unrealengine.com/en-US/download},
+}
+
+@misc{Bryan_Wirtz_SOURCE_ENGINE_2022,
+    title = {The Source Engine (Game Engine) Tutorial},
+    note = {letzer Zugriff 8.2.2022},
+    url = {https://www.gamedesigning.org/engines/source-engine/},
+    year = {2022},
+    author = {Bryan Wirtz},
+}
+
+@misc{VALVE_DEVELOPER_COMMUNITY_SOURCE2,
+    title = {Source 2},
+    note = {letzer Zugriff 8.2.2022},
+    author = {Valve Developer Community},
+    url = {https://developer.valvesoftware.com/wiki/Source_2},
+}
+
+@misc{VALVE_DEVELOPER_COMMUNITY_SOURCE,
+    title = {Source},
+    author = {Valve Developer Community},
+    url = {https://developer.valvesoftware.com/wiki/Source},
+    note = {letzer Zugriff 8.2.2022},
+}
+
+@misc{WIKIPEDIA_SOURCE_ENGINE_GAME_LIST,
+    title = {Source (game engine)},
+    note= {letzer Zugriff 8.2.2022},
+    url = {https://en.wikipedia.org/wiki/Source_(game_engine)},
+}
+
+@misc{WIKIPEDIA_SOURCE2_ENGINE_GAME_LIST,
+    title = {Source 2},
+    note = {letzer Zugriff 8.2.2022},
+    url = {https://en.wikipedia.org/wiki/Source_2},
+}
+
+@misc{Aden_Carter_2020,
+    title = {10 Top-Selling VR Games (According To Steam)},
+    url = {https://gamerant.com/top-selling-vr-games-according-steam/},
+    note = {letzer Zugriff 8.2.2022},
+    author = {Aden Carter},
+    year = {2020},
+}
+
+@misc{Brenna_Hillier_2015,
+    title = {Source Engine 2 doesn\'t have hidden costs or royalties \- but is Steam exclusive },
+    year = {2015},
+    author = {Brenna Hillier},
+    note = {letzer Zugriff 8.2.2022},
+    url = {https://www.vg247.com/source-engine-2-doesnt-have-hidden-costs-or-royalties-but-is-steam-exclusive},
+}