diff --git a/Electrical-Test-Measurement/clamp-meter.md b/Electrical-Test-Measurement/clamp-meter.md
index 0ab6369..d16bc67 100644
--- a/Electrical-Test-Measurement/clamp-meter.md
+++ b/Electrical-Test-Measurement/clamp-meter.md
@@ -20,8 +20,8 @@ https://www.hackster.io/mcmchris/diy-real-energy-meter-with-arduino-and-esp8266-
 
 ## reference
 
-    https://learn.openenergymonitor.org/electricity-monitoring/ct-sensors/how-to-build-an-arduino-energy-monitor-measuring-current-only?redirected=true
+https://learn.openenergymonitor.org/electricity-monitoring/ct-sensors/how-to-build-an-arduino-energy-monitor-measuring-current-only?redirected=true
 
-    https://learn.openenergymonitor.org/electricity-monitoring/ct-sensors/interface-with-arduino?redirected=true
+https://learn.openenergymonitor.org/electricity-monitoring/ct-sensors/interface-with-arduino?redirected=true
 
-    https://learn.openenergymonitor.org/electricity-monitoring/ct-sensors/introduction?redirected=true
\ No newline at end of file
+https://learn.openenergymonitor.org/electricity-monitoring/ct-sensors/introduction?redirected=true
\ No newline at end of file