diff --git a/include/sta/SdcClass.hh b/include/sta/SdcClass.hh
index be2f0284..46f269ac 100644
--- a/include/sta/SdcClass.hh
+++ b/include/sta/SdcClass.hh
@@ -56,6 +56,7 @@ class ClockLatency;
 class ClockInsertion;
 class ClockGroup;
 class ClockGroups;
+class PortDelay;
 
 enum class AnalysisType { single, bc_wc, ocv };
 
diff --git a/sdc/WriteSdc.cc b/sdc/WriteSdc.cc
index 1a9161d5..2b64264d 100644
--- a/sdc/WriteSdc.cc
+++ b/sdc/WriteSdc.cc
@@ -20,7 +20,6 @@
 #include <algorithm>
 #include <time.h>
 
-#include "DisallowCopyAssign.hh"
 #include "Zlib.hh"
 #include "Report.hh"
 #include "Error.hh"
@@ -46,8 +45,8 @@
 #include "DeratingFactors.hh"
 #include "Sdc.hh"
 #include "Fuzzy.hh"
-#include "WriteSdcPvt.hh"
 #include "StaState.hh"
+#include "WriteSdcPvt.hh"
 
 namespace sta {
 
diff --git a/sdc/WriteSdcPvt.hh b/sdc/WriteSdcPvt.hh
index ff5b285c..586d0fa6 100644
--- a/sdc/WriteSdcPvt.hh
+++ b/sdc/WriteSdcPvt.hh
@@ -17,6 +17,10 @@
 #pragma once
 
 #include "DisallowCopyAssign.hh"
+#include "Zlib.hh"
+#include "NetworkClass.hh"
+#include "GraphClass.hh"
+#include "Sdc.hh"
 
 namespace sta {