diff --git a/examples/animation/dumbbell-animation.cc b/examples/animation/dumbbell-animation.cc
index 7cccb2377..b3b835dfc 100644
--- a/examples/animation/dumbbell-animation.cc
+++ b/examples/animation/dumbbell-animation.cc
@@ -18,7 +18,6 @@
 
 #include <iostream>
 
-#include "ns3/core-module.h"
 #include "ns3/core-module.h"
 #include "ns3/network-module.h"
 #include "ns3/helper-module.h"
diff --git a/examples/animation/grid-animation.cc b/examples/animation/grid-animation.cc
index da156831c..791e5c4cc 100644
--- a/examples/animation/grid-animation.cc
+++ b/examples/animation/grid-animation.cc
@@ -18,7 +18,6 @@
 
 #include <iostream>
 
-#include "ns3/core-module.h"
 #include "ns3/core-module.h"
 #include "ns3/network-module.h"
 #include "ns3/helper-module.h"
diff --git a/examples/animation/star-animation.cc b/examples/animation/star-animation.cc
index 653f894b4..49e4d7c39 100644
--- a/examples/animation/star-animation.cc
+++ b/examples/animation/star-animation.cc
@@ -15,7 +15,6 @@
  *
  */
 
-#include "ns3/core-module.h"
 #include "ns3/core-module.h"
 #include "ns3/network-module.h"
 #include "ns3/helper-module.h"
diff --git a/examples/csma/csma-broadcast.cc b/examples/csma/csma-broadcast.cc
index 60c3181e7..eda97dce8 100644
--- a/examples/csma/csma-broadcast.cc
+++ b/examples/csma/csma-broadcast.cc
@@ -32,7 +32,6 @@
 #include <string>
 #include <cassert>
 
-#include "ns3/core-module.h"
 #include "ns3/core-module.h"
 #include "ns3/network-module.h"
 #include "ns3/helper-module.h"
diff --git a/examples/csma/csma-multicast.cc b/examples/csma/csma-multicast.cc
index e2ad8d06b..359f470ae 100644
--- a/examples/csma/csma-multicast.cc
+++ b/examples/csma/csma-multicast.cc
@@ -32,7 +32,6 @@
 #include <iostream>
 #include <fstream>
 
-#include "ns3/core-module.h"
 #include "ns3/core-module.h"
 #include "ns3/network-module.h"
 #include "ns3/helper-module.h"
diff --git a/examples/csma/csma-one-subnet.cc b/examples/csma/csma-one-subnet.cc
index e67cc81c5..f21be554b 100644
--- a/examples/csma/csma-one-subnet.cc
+++ b/examples/csma/csma-one-subnet.cc
@@ -30,7 +30,6 @@
 
 #include "ns3/core-module.h"
 #include "ns3/network-module.h"
-#include "ns3/core-module.h"
 #include "ns3/helper-module.h"
 
 using namespace ns3;
diff --git a/examples/csma/csma-packet-socket.cc b/examples/csma/csma-packet-socket.cc
index 820cc623a..a6dc7d170 100644
--- a/examples/csma/csma-packet-socket.cc
+++ b/examples/csma/csma-packet-socket.cc
@@ -32,7 +32,6 @@
 #include <string>
 #include <cassert>
 
-#include "ns3/core-module.h"
 #include "ns3/core-module.h"
 #include "ns3/network-module.h"
 #include "ns3/helper-module.h"
diff --git a/examples/csma/csma-ping.cc b/examples/csma/csma-ping.cc
index ee668957b..423937f3e 100644
--- a/examples/csma/csma-ping.cc
+++ b/examples/csma/csma-ping.cc
@@ -28,7 +28,6 @@
 #include <string>
 #include <cassert>
 
-#include "ns3/core-module.h"
 #include "ns3/core-module.h"
 #include "ns3/network-module.h"
 #include "ns3/helper-module.h"
diff --git a/examples/csma/csma-raw-ip-socket.cc b/examples/csma/csma-raw-ip-socket.cc
index 4403f674d..3fe43371b 100644
--- a/examples/csma/csma-raw-ip-socket.cc
+++ b/examples/csma/csma-raw-ip-socket.cc
@@ -31,7 +31,6 @@
 #include <string>
 #include <cassert>
 
-#include "ns3/core-module.h"
 #include "ns3/core-module.h"
 #include "ns3/network-module.h"
 #include "ns3/helper-module.h"
diff --git a/examples/csma/csma-star.cc b/examples/csma/csma-star.cc
index cd9d61aac..c3e5c25ea 100644
--- a/examples/csma/csma-star.cc
+++ b/examples/csma/csma-star.cc
@@ -15,7 +15,6 @@
  *
  */
 
-#include "ns3/core-module.h"
 #include "ns3/core-module.h"
 #include "ns3/network-module.h"
 #include "ns3/helper-module.h"
diff --git a/examples/emulation/emu-ping.cc b/examples/emulation/emu-ping.cc
index 7e8f1618c..59f64ed4a 100644
--- a/examples/emulation/emu-ping.cc
+++ b/examples/emulation/emu-ping.cc
@@ -53,7 +53,6 @@
 
 #include "ns3/abort.h"
 #include "ns3/core-module.h"
-#include "ns3/core-module.h"
 #include "ns3/network-module.h"
 #include "ns3/emu-module.h"
 #include "ns3/v4ping-module.h"
diff --git a/examples/emulation/emu-udp-echo.cc b/examples/emulation/emu-udp-echo.cc
index 29fc7e47e..3b5bc24aa 100644
--- a/examples/emulation/emu-udp-echo.cc
+++ b/examples/emulation/emu-udp-echo.cc
@@ -63,7 +63,6 @@
 
 #include <fstream>
 #include "ns3/core-module.h"
-#include "ns3/core-module.h"
 #include "ns3/helper-module.h"
 #include "ns3/emu-helper.h"
 
diff --git a/examples/matrix-topology/matrix-topology.cc b/examples/matrix-topology/matrix-topology.cc
index 2b0e67b78..b232badc8 100644
--- a/examples/matrix-topology/matrix-topology.cc
+++ b/examples/matrix-topology/matrix-topology.cc
@@ -46,7 +46,6 @@
 #include <cstdlib>
 #include <time.h>
 
-#include "ns3/core-module.h"
 #include "ns3/core-module.h"
 #include "ns3/network-module.h"
 #include "ns3/helper-module.h"
diff --git a/examples/mobility/ns2-mobility-trace.cc b/examples/mobility/ns2-mobility-trace.cc
index d71500bd0..84480497f 100644
--- a/examples/mobility/ns2-mobility-trace.cc
+++ b/examples/mobility/ns2-mobility-trace.cc
@@ -56,7 +56,6 @@
 
 #include "ns3/core-module.h"
 #include "ns3/mobility-module.h"
-#include "ns3/core-module.h"
 #include "ns3/helper-module.h"
 #include "ns3/mobility-module.h"
 #include "ns3/ns2-mobility-helper.h"
diff --git a/examples/mpi/simple-distributed.cc b/examples/mpi/simple-distributed.cc
index 5b18b7db8..8b96ba601 100644
--- a/examples/mpi/simple-distributed.cc
+++ b/examples/mpi/simple-distributed.cc
@@ -41,7 +41,6 @@
  * right leaf nodes output logging information when they receive the packet.
  */
 
-#include "ns3/core-module.h"
 #include "ns3/core-module.h"
 #include "ns3/network-module.h"
 #include "ns3/helper-module.h"
diff --git a/examples/mpi/third-distributed.cc b/examples/mpi/third-distributed.cc
index 20a9df088..8cdad9eef 100644
--- a/examples/mpi/third-distributed.cc
+++ b/examples/mpi/third-distributed.cc
@@ -14,7 +14,6 @@
  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  */
 
-#include "ns3/core-module.h"
 #include "ns3/core-module.h"
 #include "ns3/network-module.h"
 #include "ns3/helper-module.h"
diff --git a/examples/naming/object-names.cc b/examples/naming/object-names.cc
index 77d597abd..776a66141 100644
--- a/examples/naming/object-names.cc
+++ b/examples/naming/object-names.cc
@@ -22,7 +22,6 @@
 //              LAN
 //
 
-#include "ns3/core-module.h"
 #include "ns3/core-module.h"
 #include "ns3/helper-module.h"
 
diff --git a/examples/realtime/realtime-udp-echo.cc b/examples/realtime/realtime-udp-echo.cc
index bc99c0dc8..aab730529 100644
--- a/examples/realtime/realtime-udp-echo.cc
+++ b/examples/realtime/realtime-udp-echo.cc
@@ -27,7 +27,6 @@
 
 #include <fstream>
 #include "ns3/core-module.h"
-#include "ns3/core-module.h"
 #include "ns3/helper-module.h"
 
 using namespace ns3;
diff --git a/examples/routing/dynamic-global-routing.cc b/examples/routing/dynamic-global-routing.cc
index 01c34298e..a8deea65c 100644
--- a/examples/routing/dynamic-global-routing.cc
+++ b/examples/routing/dynamic-global-routing.cc
@@ -67,7 +67,6 @@
 #include <string>
 #include <cassert>
 
-#include "ns3/core-module.h"
 #include "ns3/core-module.h"
 #include "ns3/network-module.h"
 #include "ns3/helper-module.h"
diff --git a/examples/routing/global-injection-slash32.cc b/examples/routing/global-injection-slash32.cc
index c3d033133..4dc970f12 100644
--- a/examples/routing/global-injection-slash32.cc
+++ b/examples/routing/global-injection-slash32.cc
@@ -26,7 +26,6 @@
 
 #include "ns3/csma-net-device.h"
 #include "ns3/core-module.h"
-#include "ns3/core-module.h"
 #include "ns3/network-module.h"
 #include "ns3/helper-module.h"
 #include "ns3/ipv4-static-routing.h"
diff --git a/examples/routing/global-routing-slash32.cc b/examples/routing/global-routing-slash32.cc
index a0510d4cb..25f92459f 100644
--- a/examples/routing/global-routing-slash32.cc
+++ b/examples/routing/global-routing-slash32.cc
@@ -26,7 +26,6 @@
 
 #include "ns3/csma-net-device.h"
 #include "ns3/core-module.h"
-#include "ns3/core-module.h"
 #include "ns3/network-module.h"
 #include "ns3/helper-module.h"
 #include "ns3/ipv4-global-routing-helper.h"
diff --git a/examples/routing/mixed-global-routing.cc b/examples/routing/mixed-global-routing.cc
index 8acf4712e..014974949 100644
--- a/examples/routing/mixed-global-routing.cc
+++ b/examples/routing/mixed-global-routing.cc
@@ -36,7 +36,6 @@
 #include <string>
 #include <cassert>
 
-#include "ns3/core-module.h"
 #include "ns3/core-module.h"
 #include "ns3/network-module.h"
 #include "ns3/helper-module.h"
diff --git a/examples/routing/simple-alternate-routing.cc b/examples/routing/simple-alternate-routing.cc
index 3a15be024..16ed89dc5 100644
--- a/examples/routing/simple-alternate-routing.cc
+++ b/examples/routing/simple-alternate-routing.cc
@@ -37,7 +37,6 @@
 #include <string>
 #include <cassert>
 
-#include "ns3/core-module.h"
 #include "ns3/core-module.h"
 #include "ns3/network-module.h"
 #include "ns3/helper-module.h"
diff --git a/examples/routing/simple-global-routing.cc b/examples/routing/simple-global-routing.cc
index 37f8d6dad..443374a13 100644
--- a/examples/routing/simple-global-routing.cc
+++ b/examples/routing/simple-global-routing.cc
@@ -39,7 +39,6 @@
 #include <string>
 #include <cassert>
 
-#include "ns3/core-module.h"
 #include "ns3/core-module.h"
 #include "ns3/network-module.h"
 #include "ns3/helper-module.h"
diff --git a/examples/routing/static-routing-slash32.cc b/examples/routing/static-routing-slash32.cc
index f0d92ee4e..88b581203 100644
--- a/examples/routing/static-routing-slash32.cc
+++ b/examples/routing/static-routing-slash32.cc
@@ -26,7 +26,6 @@
 
 #include "ns3/csma-net-device.h"
 #include "ns3/core-module.h"
-#include "ns3/core-module.h"
 #include "ns3/network-module.h"
 #include "ns3/helper-module.h"
 #include "ns3/ipv4-static-routing-helper.h"
diff --git a/examples/socket/socket-bound-static-routing.cc b/examples/socket/socket-bound-static-routing.cc
index 8c3097000..50dec9343 100644
--- a/examples/socket/socket-bound-static-routing.cc
+++ b/examples/socket/socket-bound-static-routing.cc
@@ -35,7 +35,6 @@
 #include <string>
 #include <cassert>
 
-#include "ns3/core-module.h"
 #include "ns3/core-module.h"
 #include "ns3/network-module.h"
 #include "ns3/helper-module.h"
diff --git a/examples/socket/socket-bound-tcp-static-routing.cc b/examples/socket/socket-bound-tcp-static-routing.cc
index 08e0f8243..49d2310aa 100644
--- a/examples/socket/socket-bound-tcp-static-routing.cc
+++ b/examples/socket/socket-bound-tcp-static-routing.cc
@@ -35,7 +35,6 @@
 #include <string>
 #include <cassert>
 
-#include "ns3/core-module.h"
 #include "ns3/core-module.h"
 #include "ns3/network-module.h"
 #include "ns3/helper-module.h"
diff --git a/examples/tap/tap-csma-virtual-machine.cc b/examples/tap/tap-csma-virtual-machine.cc
index 0d178aace..2d639357f 100644
--- a/examples/tap/tap-csma-virtual-machine.cc
+++ b/examples/tap/tap-csma-virtual-machine.cc
@@ -63,7 +63,6 @@
 
 #include "ns3/core-module.h"
 #include "ns3/network-module.h"
-#include "ns3/core-module.h"
 #include "ns3/helper-module.h"
 
 using namespace ns3;
diff --git a/examples/tap/tap-csma.cc b/examples/tap/tap-csma.cc
index 5c31190ec..32aa3ace2 100644
--- a/examples/tap/tap-csma.cc
+++ b/examples/tap/tap-csma.cc
@@ -59,7 +59,6 @@
 
 #include "ns3/core-module.h"
 #include "ns3/network-module.h"
-#include "ns3/core-module.h"
 #include "ns3/wifi-module.h"
 #include "ns3/helper-module.h"
 #include "ns3/ipv4-global-routing-helper.h"
diff --git a/examples/tcp/star.cc b/examples/tcp/star.cc
index d1411fca6..eac8e786f 100644
--- a/examples/tcp/star.cc
+++ b/examples/tcp/star.cc
@@ -15,7 +15,6 @@
  *
  */
 
-#include "ns3/core-module.h"
 #include "ns3/core-module.h"
 #include "ns3/network-module.h"
 #include "ns3/helper-module.h"
diff --git a/examples/tcp/tcp-bulk-send.cc b/examples/tcp/tcp-bulk-send.cc
index 2ae186b72..270d938bd 100644
--- a/examples/tcp/tcp-bulk-send.cc
+++ b/examples/tcp/tcp-bulk-send.cc
@@ -27,7 +27,6 @@
 #include <string>
 #include <fstream>
 #include "ns3/core-module.h"
-#include "ns3/core-module.h"
 #include "ns3/helper-module.h"
 #include "ns3/network-module.h"
 #include "ns3/packet-sink.h"
diff --git a/examples/tcp/tcp-nsc-zoo.cc b/examples/tcp/tcp-nsc-zoo.cc
index f10a8479e..a4345e121 100644
--- a/examples/tcp/tcp-nsc-zoo.cc
+++ b/examples/tcp/tcp-nsc-zoo.cc
@@ -33,7 +33,6 @@
 #include "ns3/core-module.h"
 #include "ns3/helper-module.h"
 #include "ns3/network-module.h"
-#include "ns3/core-module.h"
 #include "ns3/ipv4-global-routing-helper.h"
 
 using namespace ns3;
diff --git a/examples/tcp/tcp-star-server.cc b/examples/tcp/tcp-star-server.cc
index 15cf3abd9..52569a9ab 100644
--- a/examples/tcp/tcp-star-server.cc
+++ b/examples/tcp/tcp-star-server.cc
@@ -48,7 +48,6 @@
 #include <string>
 #include <cassert>
 
-#include "ns3/core-module.h"
 #include "ns3/core-module.h"
 #include "ns3/network-module.h"
 #include "ns3/helper-module.h"
diff --git a/examples/topology-read/topology-example-sim.cc b/examples/topology-read/topology-example-sim.cc
index 01d4312d6..fce561595 100644
--- a/examples/topology-read/topology-example-sim.cc
+++ b/examples/topology-read/topology-example-sim.cc
@@ -29,7 +29,6 @@
 #include "ns3/core-module.h"
 #include "ns3/network-module.h"
 #include "ns3/helper-module.h"
-#include "ns3/core-module.h"
 #include "ns3/ipv4-static-routing-helper.h"
 #include "ns3/ipv4-list-routing-helper.h"
 #include "ns3/ipv4-nix-vector-helper.h"
diff --git a/examples/tutorial/first.cc b/examples/tutorial/first.cc
index efdda4926..a09492536 100644
--- a/examples/tutorial/first.cc
+++ b/examples/tutorial/first.cc
@@ -14,7 +14,6 @@
  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  */
 
-#include "ns3/core-module.h"
 #include "ns3/core-module.h"
 #include "ns3/network-module.h"
 #include "ns3/helper-module.h"
diff --git a/examples/tutorial/second.cc b/examples/tutorial/second.cc
index 06f5f4e6c..16037a2be 100644
--- a/examples/tutorial/second.cc
+++ b/examples/tutorial/second.cc
@@ -14,7 +14,6 @@
  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  */
 
-#include "ns3/core-module.h"
 #include "ns3/core-module.h"
 #include "ns3/network-module.h"
 #include "ns3/helper-module.h"
diff --git a/examples/tutorial/third.cc b/examples/tutorial/third.cc
index a5a5009c2..956bf8e0b 100644
--- a/examples/tutorial/third.cc
+++ b/examples/tutorial/third.cc
@@ -14,7 +14,6 @@
  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  */
 
-#include "ns3/core-module.h"
 #include "ns3/core-module.h"
 #include "ns3/network-module.h"
 #include "ns3/helper-module.h"
diff --git a/examples/udp-client-server/udp-client-server.cc b/examples/udp-client-server/udp-client-server.cc
index 10721f45e..872a9652f 100644
--- a/examples/udp-client-server/udp-client-server.cc
+++ b/examples/udp-client-server/udp-client-server.cc
@@ -25,7 +25,6 @@
 
 #include <fstream>
 #include "ns3/core-module.h"
-#include "ns3/core-module.h"
 #include "ns3/helper-module.h"
 
 using namespace ns3;
diff --git a/examples/udp-client-server/udp-trace-client-server.cc b/examples/udp-client-server/udp-trace-client-server.cc
index d82703071..b7b97bab5 100644
--- a/examples/udp-client-server/udp-trace-client-server.cc
+++ b/examples/udp-client-server/udp-trace-client-server.cc
@@ -25,7 +25,6 @@
 
 #include <fstream>
 #include "ns3/core-module.h"
-#include "ns3/core-module.h"
 #include "ns3/helper-module.h"
 
 using namespace ns3;
diff --git a/examples/udp/udp-echo.cc b/examples/udp/udp-echo.cc
index 956994ef8..d76836d6e 100644
--- a/examples/udp/udp-echo.cc
+++ b/examples/udp/udp-echo.cc
@@ -27,7 +27,6 @@
 
 #include <fstream>
 #include "ns3/core-module.h"
-#include "ns3/core-module.h"
 #include "ns3/helper-module.h"
 
 using namespace ns3;
diff --git a/examples/wireless/simple-wifi-frame-aggregation.cc b/examples/wireless/simple-wifi-frame-aggregation.cc
index ccfa31a78..fe797f458 100644
--- a/examples/wireless/simple-wifi-frame-aggregation.cc
+++ b/examples/wireless/simple-wifi-frame-aggregation.cc
@@ -18,7 +18,6 @@
  * Author: Mirko Banchi <mk.banchi@gmail.com>
  */
 #include "ns3/core-module.h"
-#include "ns3/core-module.h"
 #include "ns3/network-module.h"
 #include "ns3/helper-module.h"
 #include "ns3/wifi-module.h"
diff --git a/examples/wireless/wifi-wired-bridging.cc b/examples/wireless/wifi-wired-bridging.cc
index 39905b19d..3edfa260b 100644
--- a/examples/wireless/wifi-wired-bridging.cc
+++ b/examples/wireless/wifi-wired-bridging.cc
@@ -43,7 +43,6 @@
 //               +---------+              +---------+
 //
 
-#include "ns3/core-module.h"
 #include "ns3/core-module.h"
 #include "ns3/mobility-module.h"
 #include "ns3/helper-module.h"
diff --git a/samples/main-random-topology.cc b/samples/main-random-topology.cc
index ea070a598..37ce41168 100644
--- a/samples/main-random-topology.cc
+++ b/samples/main-random-topology.cc
@@ -2,7 +2,6 @@
 
 #include "ns3/core-module.h"
 #include "ns3/mobility-module.h"
-#include "ns3/core-module.h"
 #include "ns3/helper-module.h"
 
 using namespace ns3;
diff --git a/samples/main-random-walk.cc b/samples/main-random-walk.cc
index e5893f6b7..c02e12a8a 100644
--- a/samples/main-random-walk.cc
+++ b/samples/main-random-walk.cc
@@ -3,7 +3,6 @@
 #include "ns3/core-module.h"
 #include "ns3/helper-module.h"
 #include "ns3/mobility-module.h"
-#include "ns3/core-module.h"
 
 using namespace ns3;
 
diff --git a/samples/main-simple.cc b/samples/main-simple.cc
index 172cb1951..c2700e449 100644
--- a/samples/main-simple.cc
+++ b/samples/main-simple.cc
@@ -3,7 +3,6 @@
 #include "ns3/core-module.h"
 #include "ns3/helper-module.h"
 #include "ns3/network-module.h"
-#include "ns3/core-module.h"
 
 using namespace ns3;
 
diff --git a/scratch/multiple-sources/simple-simulation.cc b/scratch/multiple-sources/simple-simulation.cc
index be6dc5812..03cb5f444 100644
--- a/scratch/multiple-sources/simple-simulation.cc
+++ b/scratch/multiple-sources/simple-simulation.cc
@@ -3,7 +3,6 @@
 #include "ns3/core-module.h"
 #include "ns3/helper-module.h"
 #include "ns3/network-module.h"
-#include "ns3/core-module.h"
 
 using namespace ns3;
 
diff --git a/scratch/simple.cc b/scratch/simple.cc
index d8be40db0..27bdaee2e 100644
--- a/scratch/simple.cc
+++ b/scratch/simple.cc
@@ -3,7 +3,6 @@
 #include "ns3/core-module.h"
 #include "ns3/helper-module.h"
 #include "ns3/network-module.h"
-#include "ns3/core-module.h"
 
 using namespace ns3;
 
diff --git a/src/devices/bridge/examples/csma-bridge-one-hop.cc b/src/devices/bridge/examples/csma-bridge-one-hop.cc
index 4d8fbac63..80b26e4a1 100644
--- a/src/devices/bridge/examples/csma-bridge-one-hop.cc
+++ b/src/devices/bridge/examples/csma-bridge-one-hop.cc
@@ -71,7 +71,6 @@
 
 #include "ns3/core-module.h"
 #include "ns3/network-module.h"
-#include "ns3/core-module.h"
 #include "ns3/helper-module.h"
 #include "ns3/bridge-module.h"
 #include "ns3/ipv4-global-routing-helper.h"
diff --git a/src/devices/bridge/examples/csma-bridge.cc b/src/devices/bridge/examples/csma-bridge.cc
index 84eec3502..7adcd5416 100644
--- a/src/devices/bridge/examples/csma-bridge.cc
+++ b/src/devices/bridge/examples/csma-bridge.cc
@@ -34,7 +34,6 @@
 
 #include "ns3/core-module.h"
 #include "ns3/network-module.h"
-#include "ns3/core-module.h"
 #include "ns3/helper-module.h"
 #include "ns3/bridge-module.h"
 
diff --git a/src/devices/virtual-net-device/examples/virtual-net-device.cc b/src/devices/virtual-net-device/examples/virtual-net-device.cc
index 876055f7c..026019ea1 100644
--- a/src/devices/virtual-net-device/examples/virtual-net-device.cc
+++ b/src/devices/virtual-net-device/examples/virtual-net-device.cc
@@ -51,7 +51,6 @@
 #include <string>
 #include <cassert>
 
-#include "ns3/core-module.h"
 #include "ns3/core-module.h"
 #include "ns3/network-module.h"
 #include "ns3/helper-module.h"
diff --git a/src/routing/olsr/examples/simple-point-to-point-olsr.cc b/src/routing/olsr/examples/simple-point-to-point-olsr.cc
index ba4ec971a..efcb569d2 100644
--- a/src/routing/olsr/examples/simple-point-to-point-olsr.cc
+++ b/src/routing/olsr/examples/simple-point-to-point-olsr.cc
@@ -40,7 +40,6 @@
 #include <string>
 #include <cassert>
 
-#include "ns3/core-module.h"
 #include "ns3/core-module.h"
 #include "ns3/network-module.h"
 #include "ns3/helper-module.h"
diff --git a/src/test/perf/perf-io.cc b/src/test/perf/perf-io.cc
index 8a27be527..b40d7f900 100644
--- a/src/test/perf/perf-io.cc
+++ b/src/test/perf/perf-io.cc
@@ -25,7 +25,6 @@
 
 #include "ns3/core-module.h"
 #include "ns3/network-module.h"
-#include "ns3/core-module.h"
 #include "ns3/helper-module.h"
 #include "ns3/abort.h"
 
diff --git a/utils/bench-simulator.cc b/utils/bench-simulator.cc
index 646042372..a5927ba30 100644
--- a/utils/bench-simulator.cc
+++ b/utils/bench-simulator.cc
@@ -18,7 +18,6 @@
  * Author: Mathieu Lacage <mathieu.lacage@sophia.inria.fr>
  */
 
-#include "ns3/core-module.h"
 #include "ns3/core-module.h"
 #include <iostream>
 #include <fstream>