diff --git a/src/keystore.h b/src/keystore.h
index 349c64b91d..eb8bde9ccb 100644
--- a/src/keystore.h
+++ b/src/keystore.h
@@ -29,7 +29,7 @@ class CKeyStore
     virtual void GetKeys(std::set<CKeyID> &setAddress) const =0;
     virtual bool GetPubKey(const CKeyID &address, CPubKey& vchPubKeyOut) const;
 
-    // Support for BIP 0013 : see https://en.bitcoin.it/wiki/BIP_0013
+    // Support for BIP 0013 : see https://github.com/bitcoin/bips/blob/master/bip-0013.mediawiki
     virtual bool AddCScript(const CScript& redeemScript) =0;
     virtual bool HaveCScript(const CScriptID &hash) const =0;
     virtual bool GetCScript(const CScriptID &hash, CScript& redeemScriptOut) const =0;
diff --git a/src/qt/bitcoinaddressvalidator.h b/src/qt/bitcoinaddressvalidator.h
index 2f83271992..f72f9359a7 100644
--- a/src/qt/bitcoinaddressvalidator.h
+++ b/src/qt/bitcoinaddressvalidator.h
@@ -3,8 +3,8 @@
 
 #include <QRegExpValidator>
 
-/** Base48 entry widget validator.
-   Corrects near-miss characters and refuses characters that are no part of base48.
+/** Base58 entry widget validator.
+   Corrects near-miss characters and refuses characters that are no part of base58.
  */
 class BitcoinAddressValidator : public QValidator
 {
diff --git a/src/rpc/protocol.cpp b/src/rpc/protocol.cpp
index 6ad6b01a41..bfff49a7bb 100644
--- a/src/rpc/protocol.cpp
+++ b/src/rpc/protocol.cpp
@@ -218,7 +218,7 @@ int ReadHTTPMessage(std::basic_istream<char>& stream, std::map<std::string,
 // unspecified (HTTP errors and contents of 'error').
 //
 // 1.0 spec: http://json-rpc.org/wiki/specification
-// 1.2 spec: http://groups.google.com/group/json-rpc/web/json-rpc-over-http
+// 1.2 spec: http://jsonrpc.org/historical/json-rpc-over-http.html
 // https://www.codeproject.com/KB/recipes/JSON_Spirit.aspx
 //
 
diff --git a/src/test/bignum_tests.cpp b/src/test/bignum_tests.cpp
index 0caf191cc1..bc29a7023a 100755
--- a/src/test/bignum_tests.cpp
+++ b/src/test/bignum_tests.cpp
@@ -36,11 +36,8 @@ BOOST_AUTO_TEST_SUITE(bignum_tests)
 // stack buffer overruns.
 //
 // For more accurate diagnostics, you can use an undefined arithmetic operation
-// detector such as the clang-based tool:
-//
-// "IOC: An Integer Overflow Checker for C/C++"
-//
-// Available at: http://embed.cs.utah.edu/ioc/
+// detector such as the clang's undefined behaviour checker.
+// See also: http://clang.llvm.org/docs/UsersManual.html#controlling-code-generation
 //
 // It might also be useful to use Google's AddressSanitizer to detect
 // stack buffer overruns, which valgrind can't currently detect.
diff --git a/src/test/netbase_tests.cpp b/src/test/netbase_tests.cpp
index ebc5e968cc..6789263caa 100644
--- a/src/test/netbase_tests.cpp
+++ b/src/test/netbase_tests.cpp
@@ -91,7 +91,7 @@ BOOST_AUTO_TEST_CASE(netbase_lookupnumeric)
 
 BOOST_AUTO_TEST_CASE(onioncat_test)
 {
-    // values from http://www.cypherpunk.at/onioncat/wiki/OnionCat
+    // values from https://web.archive.org/web/20121122003543/http://www.cypherpunk.at/onioncat/wiki/OnionCat
     CNetAddr addr1("5wyqrzbvrdsumnok.onion");
     CNetAddr addr2("FD87:D87E:EB43:edb1:8e4:3588:e546:35ca");
     BOOST_CHECK(addr1 == addr2);