diff --git a/src/commands/CmdReports.cpp b/src/commands/CmdReports.cpp
index f6a70d2e0..2901a02df 100644
--- a/src/commands/CmdReports.cpp
+++ b/src/commands/CmdReports.cpp
@@ -26,6 +26,7 @@
 ////////////////////////////////////////////////////////////////////////////////
 
 #include <sstream>
+#include <algorithm>
 #include <Context.h>
 #include <ViewText.h>
 #include <text.h>
diff --git a/src/commands/CmdSummary.cpp b/src/commands/CmdSummary.cpp
index 6cffa6add..87a9c2002 100644
--- a/src/commands/CmdSummary.cpp
+++ b/src/commands/CmdSummary.cpp
@@ -26,6 +26,7 @@
 ////////////////////////////////////////////////////////////////////////////////
 
 #include <sstream>
+#include <stdlib.h>
 #include <Context.h>
 #include <ViewText.h>
 #include <Duration.h>
@@ -96,7 +97,7 @@ int CmdSummary::execute (const std::string&, std::string& output)
     {
       ++countPending[project];
 
-      time_t entry = atoi (task->get ("entry").c_str ());
+      time_t entry = strtol (task->get ("entry").c_str (), NULL, 10);
       if (entry)
         sumEntry[project] = sumEntry[project] + (double) (now - entry);
     }
@@ -105,8 +106,8 @@ int CmdSummary::execute (const std::string&, std::string& output)
     {
       ++countCompleted[project];
 
-      time_t entry = atoi (task->get ("entry").c_str ());
-      time_t end   = atoi (task->get ("end").c_str ());
+      time_t entry = strtol (task->get ("entry").c_str (), NULL, 10);
+      time_t end   = strtol (task->get ("end").c_str (), NULL, 10);
       if (entry && end)
         sumEntry[project] = sumEntry[project] + (double) (end - entry);
     }
diff --git a/src/commands/CmdTimesheet.cpp b/src/commands/CmdTimesheet.cpp
index 52b7efc95..a6fcc3722 100644
--- a/src/commands/CmdTimesheet.cpp
+++ b/src/commands/CmdTimesheet.cpp
@@ -26,6 +26,7 @@
 ////////////////////////////////////////////////////////////////////////////////
 
 #include <sstream>
+#include <stdlib.h>
 #include <Context.h>
 #include <ViewText.h>
 #include <Date.h>
@@ -109,7 +110,7 @@ int CmdTimesheet::execute (const std::string&, std::string& output)
       // If task completed within range.
       if (task->getStatus () == Task::completed)
       {
-        Date compDate (atoi (task->get ("end").c_str ()));
+        Date compDate (strtol (task->get ("end").c_str (), NULL, 10));
         if (compDate >= start && compDate < end)
         {
           Color c (task->get ("fg") + " " + task->get ("bg"));
@@ -147,7 +148,7 @@ int CmdTimesheet::execute (const std::string&, std::string& output)
       if (task->getStatus () == Task::pending &&
           task->has ("start"))
       {
-        Date startDate (atoi (task->get ("start").c_str ()));
+        Date startDate (strtol (task->get ("start").c_str (), NULL, 10));
         if (startDate >= start && startDate < end)
         {
           Color c (task->get ("fg") + " " + task->get ("bg"));