diff --git a/examples/reprojection-by-code.html b/examples/reprojection-by-code.html
index 446aee77b6..319309832a 100644
--- a/examples/reprojection-by-code.html
+++ b/examples/reprojection-by-code.html
@@ -7,8 +7,6 @@ docs: >
   OSM (EPSG:3857) to arbitrary projection by searching
   in <a href="https://epsg.io/">EPSG.io</a> database.
 tags: "reprojection, projection, proj4js, epsg.io"
-resources:
-  - https://cdnjs.cloudflare.com/ajax/libs/proj4js/2.4.4/proj4.js
 ---
 <div id="map" class="map"></div>
 <form class="form-inline">
diff --git a/examples/reprojection-by-code.js b/examples/reprojection-by-code.js
index 3503d6e425..451836c0f0 100644
--- a/examples/reprojection-by-code.js
+++ b/examples/reprojection-by-code.js
@@ -6,6 +6,7 @@ import {get as getProjection, getTransform} from '../src/ol/proj.js';
 import {register} from '../src/ol/proj/proj4.js';
 import _ol_source_OSM_ from '../src/ol/source/OSM.js';
 import _ol_source_TileImage_ from '../src/ol/source/TileImage.js';
+import proj4 from 'proj4';
 
 
 var map = new _ol_Map_({
diff --git a/examples/reprojection.html b/examples/reprojection.html
index b87a7776a9..dee4de0364 100644
--- a/examples/reprojection.html
+++ b/examples/reprojection.html
@@ -5,8 +5,6 @@ shortdesc: Demonstrates client-side raster reprojection between various projecti
 docs: >
   This example shows client-side raster reprojection between various projections.
 tags: "reprojection, projection, proj4js, osm, wms, wmts, hidpi"
-resources:
-  - https://cdnjs.cloudflare.com/ajax/libs/proj4js/2.4.4/proj4.js
 ---
 <div id="map" class="map"></div>
 <form class="form-inline">
diff --git a/examples/reprojection.js b/examples/reprojection.js
index c166c018c7..376e38f942 100644
--- a/examples/reprojection.js
+++ b/examples/reprojection.js
@@ -11,6 +11,7 @@ import _ol_source_TileWMS_ from '../src/ol/source/TileWMS.js';
 import _ol_source_WMTS_ from '../src/ol/source/WMTS.js';
 import _ol_source_XYZ_ from '../src/ol/source/XYZ.js';
 import _ol_tilegrid_TileGrid_ from '../src/ol/tilegrid/TileGrid.js';
+import proj4 from 'proj4';
 
 
 proj4.defs('EPSG:27700', '+proj=tmerc +lat_0=49 +lon_0=-2 +k=0.9996012717 ' +
diff --git a/examples/scaleline-indiana-east.html b/examples/scaleline-indiana-east.html
index 40d9dfe109..787539cb2d 100644
--- a/examples/scaleline-indiana-east.html
+++ b/examples/scaleline-indiana-east.html
@@ -5,7 +5,5 @@ shortdesc: Demonstrates client-side reprojection of OpenStreetMap to NAD83 India
 docs: >
   This example shows client-side reprojection of OpenStreetMap to NAD83 Indiana East, including a ScaleLine control with US units.
 tags: "reprojection, projection, openstreetmap, nad83, tile, scaleline"
-resources:
-  - https://cdnjs.cloudflare.com/ajax/libs/proj4js/2.4.4/proj4.js
 ---
 <div id="map" class="map"></div>
diff --git a/examples/scaleline-indiana-east.js b/examples/scaleline-indiana-east.js
index 372e01299a..d203095eaa 100644
--- a/examples/scaleline-indiana-east.js
+++ b/examples/scaleline-indiana-east.js
@@ -5,6 +5,7 @@ import _ol_layer_Tile_ from '../src/ol/layer/Tile.js';
 import {fromLonLat, transformExtent} from '../src/ol/proj.js';
 import {register} from '../src/ol/proj/proj4.js';
 import _ol_source_OSM_ from '../src/ol/source/OSM.js';
+import proj4 from 'proj4';
 
 proj4.defs('Indiana-East', 'PROJCS["IN83-EF",GEOGCS["LL83",DATUM["NAD83",' +
     'SPHEROID["GRS1980",6378137.000,298.25722210]],PRIMEM["Greenwich",0],' +
diff --git a/examples/sphere-mollweide.html b/examples/sphere-mollweide.html
index 13286a4a39..f57a4ccb25 100644
--- a/examples/sphere-mollweide.html
+++ b/examples/sphere-mollweide.html
@@ -5,7 +5,5 @@ shortdesc: Example of a Sphere Mollweide map with a Graticule component.
 docs: >
   Example of a Sphere Mollweide map with a Graticule component.
 tags: "graticule, Mollweide, projection, proj4js"
-resources:
-  - https://cdnjs.cloudflare.com/ajax/libs/proj4js/2.4.4/proj4.js
 ---
 <div id="map" class="map"></div>
diff --git a/examples/sphere-mollweide.js b/examples/sphere-mollweide.js
index a7b79d7482..08552b07fc 100644
--- a/examples/sphere-mollweide.js
+++ b/examples/sphere-mollweide.js
@@ -6,6 +6,7 @@ import _ol_layer_Vector_ from '../src/ol/layer/Vector.js';
 import _ol_proj_Projection_ from '../src/ol/proj/Projection.js';
 import _ol_source_Vector_ from '../src/ol/source/Vector.js';
 import {register} from '../src/ol/proj/proj4.js';
+import proj4 from 'proj4';
 
 
 proj4.defs('ESRI:53009', '+proj=moll +lon_0=0 +x_0=0 +y_0=0 +a=6371000 ' +
diff --git a/examples/wms-image-custom-proj.html b/examples/wms-image-custom-proj.html
index 9ae33190df..5e65f72590 100644
--- a/examples/wms-image-custom-proj.html
+++ b/examples/wms-image-custom-proj.html
@@ -5,8 +5,5 @@ shortdesc: Example of integrating Proj4js for coordinate transforms.
 docs: >
   With [Proj4js](http://proj4js.org/) integration, OpenLayers can transform coordinates between arbitrary projections.
 tags: "wms, single image, proj4js, projection"
-resources:
-  - https://cdnjs.cloudflare.com/ajax/libs/proj4js/2.4.4/proj4.js
-  - https://epsg.io/21781-1753.js
 ---
 <div id="map" class="map"></div>
diff --git a/examples/wms-image-custom-proj.js b/examples/wms-image-custom-proj.js
index affde84526..95ebb489c5 100644
--- a/examples/wms-image-custom-proj.js
+++ b/examples/wms-image-custom-proj.js
@@ -7,23 +7,26 @@ import {fromLonLat} from '../src/ol/proj.js';
 import _ol_proj_Projection_ from '../src/ol/proj/Projection.js';
 import _ol_source_ImageWMS_ from '../src/ol/source/ImageWMS.js';
 import {register} from '../src/ol/proj/proj4.js';
+import proj4 from 'proj4';
 
 
 // Transparent Proj4js support:
 //
-// EPSG:21781 is known to Proj4js because its definition was loaded in the html.
-// Now when we create an ol.proj.Projection instance with the 'EPSG:21781' code,
-// OpenLayers will pick up parameters like units and transform functions from
-// Proj4js.
+// EPSG:21781 is known to Proj4js because its definition is registered by
+// calling proj4.defs(). Now when we create an ol/proj/Projection instance with
+// the 'EPSG:21781' code, OpenLayers will pick up the transform functions from
+// Proj4js. To get the registered ol/proj/Projection instance with other
+// parameters like units and axis orientation applied from Proj4js, use
+// `ol/proj#get('EPSG:21781')`.
 //
 // Note that we are setting the projection's extent here, which is used to
 // determine the view resolution for zoom level 0. Recommended values for a
 // projection's validity extent can be found at https://epsg.io/.
-//
-// If you use Proj4js only to transform coordinates, you don't even need to
-// create an ol.proj.Projection instance. ol.proj.get() will take care of it
-// internally.
 
+proj4.defs('EPSG:21781',
+    '+proj=somerc +lat_0=46.95240555555556 +lon_0=7.439583333333333 +k_0=1 ' +
+    '+x_0=600000 +y_0=200000 +ellps=bessel ' +
+    '+towgs84=660.077,13.551,369.344,2.484,1.783,2.939,5.66 +units=m +no_defs');
 register(proj4);
 
 var projection = new _ol_proj_Projection_({