diff --git a/core/common.hpp b/core/common.hpp
index b0fc450..2678a17 100644
--- a/core/common.hpp
+++ b/core/common.hpp
@@ -91,8 +91,8 @@
 using std::const_pointer_cast;
 
 using std::bind;
-using std::cref;
-using std::ref;
+
+using namespace std::string_literals;
 
 using ndn::optional;
 using ndn::nullopt;
diff --git a/core/manager-base.hpp b/core/manager-base.hpp
index cddb7c1..a19ccb2 100644
--- a/core/manager-base.hpp
+++ b/core/manager-base.hpp
@@ -161,7 +161,7 @@
   m_dispatcher.addControlCommand<ControlParameters>(
     makeRelPrefix(verb),
     makeAuthorization(verb),
-    bind(&ManagerBase::validateParameters, cref(*command), _1),
+    bind(&ManagerBase::validateParameters, std::cref(*command), _1),
     bind(&ManagerBase::handleCommand, command, handler, _1, _2, _3, _4));
 }
 
diff --git a/core/network-predicate.cpp b/core/network-predicate.cpp
index 5755f32..d10a5e3 100644
--- a/core/network-predicate.cpp
+++ b/core/network-predicate.cpp
@@ -193,8 +193,8 @@
 bool
 NetworkInterfacePredicate::operator()(const ndn::net::NetworkInterface& netif) const
 {
-  return std::any_of(m_whitelist.begin(), m_whitelist.end(), bind(&doesNetifMatchRule, cref(netif), _1)) &&
-         std::none_of(m_blacklist.begin(), m_blacklist.end(), bind(&doesNetifMatchRule, cref(netif), _1));
+  return std::any_of(m_whitelist.begin(), m_whitelist.end(), bind(&doesNetifMatchRule, std::cref(netif), _1)) &&
+         std::none_of(m_blacklist.begin(), m_blacklist.end(), bind(&doesNetifMatchRule, std::cref(netif), _1));
 }
 
 static bool
@@ -214,8 +214,8 @@
 bool
 IpAddressPredicate::operator()(const boost::asio::ip::address& address) const
 {
-  return std::any_of(m_whitelist.begin(), m_whitelist.end(), bind(&doesAddressMatchRule, cref(address), _1)) &&
-         std::none_of(m_blacklist.begin(), m_blacklist.end(), bind(&doesAddressMatchRule, cref(address), _1));
+  return std::any_of(m_whitelist.begin(), m_whitelist.end(), bind(&doesAddressMatchRule, std::cref(address), _1)) &&
+         std::none_of(m_blacklist.begin(), m_blacklist.end(), bind(&doesAddressMatchRule, std::cref(address), _1));
 }
 
 } // namespace nfd
diff --git a/core/rtt-estimator.hpp b/core/rtt-estimator.hpp
index 2b93880..e8a5eb9 100644
--- a/core/rtt-estimator.hpp
+++ b/core/rtt-estimator.hpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
-/**
- * Copyright (c) 2014-2017,  Regents of the University of California,
+/*
+ * Copyright (c) 2014-2018,  Regents of the University of California,
  *                           Arizona Board of Regents,
  *                           Colorado State University,
  *                           University Pierre & Marie Curie, Sorbonne University,
@@ -33,7 +33,7 @@
 /**
  * \brief implements the Mean-Deviation RTT estimator
  *
- * reference: ns3::RttMeanDeviation
+ * \sa ns3::RttMeanDeviation
  *
  * This RttEstimator algorithm is designed for TCP, which is a continuous stream.
  * NDN Interest-Data traffic is not always a continuous stream,
@@ -43,18 +43,18 @@
 class RttEstimator
 {
 public:
-  typedef time::microseconds Duration;
-
-  static Duration
-  getInitialRtt(void)
-  {
-    return time::seconds(1);
-  }
+  using Duration = time::microseconds;
 
   RttEstimator(uint16_t maxMultiplier = 16,
-               Duration minRto = time::milliseconds(1),
+               Duration minRto = 1_ms,
                double gain = 0.1);
 
+  static Duration
+  getInitialRtt()
+  {
+    return 1_s;
+  }
+
   void
   addMeasurement(Duration measure);