diff --git a/doc/api/dgram.md b/doc/api/dgram.md
index 2cda70fa62bc13..894f64f36e135f 100644
--- a/doc/api/dgram.md
+++ b/doc/api/dgram.md
@@ -123,7 +123,7 @@ if (cluster.isMaster) {
 }
 ```
 
-### socket.addSourceSpecificMembership(sourceAddress, groupAddress[, multicastInterface])
+### socket.addSourceSpecificMembership(sourceAddress, groupAddress\[, multicastInterface\])
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@@ -312,7 +312,7 @@ never have reason to call this.
 If `multicastInterface` is not specified, the operating system will attempt to
 drop membership on all valid interfaces.
 
-### socket.dropSourceSpecificMembership(sourceAddress, groupAddress[, multicastInterface])
+### socket.dropSourceSpecificMembership(sourceAddress, groupAddress\[, multicastInterface\])
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