diff --git a/PepLib/Drawing.cs b/PepLib/Drawing.cs
index 7dc816b..82a640b 100644
--- a/PepLib/Drawing.cs
+++ b/PepLib/Drawing.cs
@@ -1,6 +1,7 @@
 using System;
 using System.Collections.Generic;
 using System.IO;
+using PepLib.Codes;
 using PepLib.IO;
 
 namespace PepLib
@@ -30,6 +31,58 @@ namespace PepLib
             return reader.Drawing;
         }
 
+        public void ResolveLoops()
+        {
+            for (int i = 0; i < Loops.Count; ++i)
+            {
+                var loop = Loops[i];
+                ResolveLoops(loop);
+            }
+        }
+
+        private void ResolveLoops(Program pgm)
+        {
+            for (int i = 0; i < pgm.Count; ++i)
+            {
+                var code = pgm[i];
+
+                if (code.CodeType() != CodeType.SubProgramCall)
+                    continue;
+
+                var subpgmcall = (SubProgramCall)code;
+
+                var loop = GetLoop(subpgmcall.LoopId);
+
+                if (loop == null)
+                    throw new Exception("Loop not found");
+
+                subpgmcall.Loop = loop;
+            }
+        }
+
+        public Loop GetLoop(int id)
+        {
+            string name = GetLoopName(id);
+            return GetLoop(name);
+        }
+
+
+        private Loop GetLoop(string name)
+        {
+            for (int i = 0; i < Loops.Count; ++i)
+            {
+                if (Loops[i].Name == name)
+                    return Loops[i];
+            }
+
+            return null;
+        }
+
+        private string GetLoopName(int loopId)
+        {
+            return string.Format("{0}.loop-{1}", Info.Name, loopId.ToString().PadLeft(3, '0'));
+        }
+
         public static bool TryLoad(string nestfile, out Drawing drawing)
         {
             try
diff --git a/PepLib/IO/DrawingReader.cs b/PepLib/IO/DrawingReader.cs
index b9396c0..153eda0 100644
--- a/PepLib/IO/DrawingReader.cs
+++ b/PepLib/IO/DrawingReader.cs
@@ -22,7 +22,6 @@ namespace PepLib.IO
 
         public void Read(Stream stream)
         {
-            var drawing = new Drawing();
             var zipStream = new ZipInputStream(stream);
 
             ZipEntry theEntry;
@@ -58,12 +57,14 @@ namespace PepLib.IO
                 }
 
                 if (Regex.IsMatch(extension, "loop-\\d\\d\\d"))
-                    drawing.Loops.Add(ReadLoop(theEntry.FileName, memstream));
+                    Drawing.Loops.Add(ReadLoop(theEntry.FileName, memstream));
 
                 memstream.Close();
             }
 
             zipStream.Close();
+
+            Drawing.ResolveLoops();
         }
 
         public void Read(string nestFile)
diff --git a/PepLib/PepLib.csproj b/PepLib/PepLib.csproj
index e093a63..719ed4a 100644
--- a/PepLib/PepLib.csproj
+++ b/PepLib/PepLib.csproj
@@ -33,8 +33,8 @@
     <Prefer32Bit>false</Prefer32Bit>
   </PropertyGroup>
   <ItemGroup>
-    <Reference Include="DotNetZip, Version=1.12.0.0, Culture=neutral, PublicKeyToken=6583c7c814667745, processorArchitecture=MSIL">
-      <HintPath>..\packages\DotNetZip.1.12.0\lib\net20\DotNetZip.dll</HintPath>
+    <Reference Include="DotNetZip, Version=1.13.3.0, Culture=neutral, PublicKeyToken=6583c7c814667745, processorArchitecture=MSIL">
+      <HintPath>..\..\packages\DotNetZip.1.13.3\lib\net40\DotNetZip.dll</HintPath>
     </Reference>
     <Reference Include="System" />
   </ItemGroup>
diff --git a/PepLib/packages.config b/PepLib/packages.config
index fa0019f..6438d2c 100644
--- a/PepLib/packages.config
+++ b/PepLib/packages.config
@@ -1,4 +1,4 @@
 <?xml version="1.0" encoding="utf-8"?>
 <packages>
-  <package id="DotNetZip" version="1.12.0" targetFramework="net461" />
+  <package id="DotNetZip" version="1.13.3" targetFramework="net461" />
 </packages>
\ No newline at end of file