diff --git a/ClosedXML/Excel/CalcEngine/Functions/MathTrig.cs b/ClosedXML/Excel/CalcEngine/Functions/MathTrig.cs
index 688db07..ee73ea1 100644
--- a/ClosedXML/Excel/CalcEngine/Functions/MathTrig.cs
+++ b/ClosedXML/Excel/CalcEngine/Functions/MathTrig.cs
@@ -4,6 +4,7 @@
 using System.Collections;
 using System.Collections.Generic;
 using System.Linq;
+using System.Text;
 
 namespace ClosedXML.Excel.CalcEngine
 {
@@ -26,6 +27,7 @@
             ce.RegisterFunction("COS", 1, Cos);
             ce.RegisterFunction("COSH", 1, Cosh);
             ce.RegisterFunction("CSCH", 1, Csch);
+            ce.RegisterFunction("DECIMAL", 2, MathTrig.Decimal);
             ce.RegisterFunction("DEGREES", 1, Degrees);
             ce.RegisterFunction("EVEN", 1, Even);
             ce.RegisterFunction("EXP", 1, Exp);
@@ -124,6 +126,40 @@
             return 1 / Math.Sinh(p[0]);
         }
 
+        private static object Decimal(List<Expression> p)
+        {
+            string source = p[0];
+            double radix = p[1];
+
+            if (radix < 2 || radix > 36)
+                throw new NumberException();
+
+            var asciiValues = Encoding.ASCII.GetBytes(source.ToUpperInvariant());
+
+            double result = 0;
+            int i = 0;
+
+            foreach (byte digit in asciiValues)
+            {
+                if (digit > 90)
+                {
+                    throw new NumberException();
+                }
+
+                int digitNumber = digit >= 48 && digit < 58
+                    ? digit - 48
+                    : digit - 55;
+
+                if (digitNumber > radix - 1)
+                    throw new NumberException();
+
+                result = result * radix + digitNumber;
+                i++;
+            }
+
+            return result;
+        }
+
         private static object Exp(List<Expression> p)
         {
             return Math.Exp(p[0]);
diff --git a/ClosedXML/Excel/XLWorkbook_Load.cs b/ClosedXML/Excel/XLWorkbook_Load.cs
index 549357b..3af1993 100644
--- a/ClosedXML/Excel/XLWorkbook_Load.cs
+++ b/ClosedXML/Excel/XLWorkbook_Load.cs
@@ -728,8 +728,10 @@
 
         private static IXLMarker LoadMarker(IXLWorksheet ws, Xdr.MarkerType marker)
         {
+            var row = Math.Max(1, Convert.ToInt32(marker.RowId.InnerText) + 1);
+            var column = Math.Min(XLHelper.MaxColumnNumber, Convert.ToInt32(marker.ColumnId.InnerText) + 1);
             return new XLMarker(
-                ws.Cell(Convert.ToInt32(marker.RowId.InnerText) + 1, Convert.ToInt32(marker.ColumnId.InnerText) + 1).Address,
+                ws.Cell(row, column).Address,
                 new Point(
                     ConvertFromEnglishMetricUnits(Convert.ToInt32(marker.ColumnOffset.InnerText), GraphicsUtils.Graphics.DpiX),
                     ConvertFromEnglishMetricUnits(Convert.ToInt32(marker.RowOffset.InnerText), GraphicsUtils.Graphics.DpiY)
diff --git a/ClosedXML/Excel/XLWorkbook_Save.cs b/ClosedXML/Excel/XLWorkbook_Save.cs
index d80ed6f..a60076a 100644
--- a/ClosedXML/Excel/XLWorkbook_Save.cs
+++ b/ClosedXML/Excel/XLWorkbook_Save.cs
@@ -148,19 +148,18 @@
 
             string sheetName = worksheet.Name;
             // Get the pivot Table Parts
-            IEnumerable<PivotTableCacheDefinitionPart> pvtTableCacheParts = wbPart.PivotTableCacheDefinitionParts;
-            Dictionary<PivotTableCacheDefinitionPart, string> pvtTableCacheDefinationPart = new Dictionary<PivotTableCacheDefinitionPart, string>();
+            var pvtTableCacheParts = wbPart.PivotTableCacheDefinitionParts;
+            var pvtTableCacheDefinitionPart = new Dictionary<PivotTableCacheDefinitionPart, string>();
             foreach (PivotTableCacheDefinitionPart Item in pvtTableCacheParts)
             {
                 PivotCacheDefinition pvtCacheDef = Item.PivotCacheDefinition;
                 //Check if this CacheSource is linked to SheetToDelete
-                var pvtCache = pvtCacheDef.Descendants<CacheSource>().Where(s => s.WorksheetSource.Sheet == sheetName);
-                if (pvtCache.Any())
+                if (pvtCacheDef.Descendants<CacheSource>().Any(s => s.WorksheetSource != null && s.WorksheetSource.Sheet == sheetName))
                 {
-                    pvtTableCacheDefinationPart.Add(Item, Item.ToString());
+                    pvtTableCacheDefinitionPart.Add(Item, Item.ToString());
                 }
             }
-            foreach (var Item in pvtTableCacheDefinationPart)
+            foreach (var Item in pvtTableCacheDefinitionPart)
             {
                 wbPart.DeletePart(Item.Key);
             }
diff --git a/ClosedXML_Tests/Excel/CalcEngine/MathTrigTests.cs b/ClosedXML_Tests/Excel/CalcEngine/MathTrigTests.cs
index ada5f7f..df319ad 100644
--- a/ClosedXML_Tests/Excel/CalcEngine/MathTrigTests.cs
+++ b/ClosedXML_Tests/Excel/CalcEngine/MathTrigTests.cs
@@ -12,6 +12,33 @@
     {
         private readonly double tolerance = 1e-10;
 
+        [TestCase("FF", 16, 255)]
+        [TestCase("111", 2, 7)]
+        [TestCase("zap", 36, 45745)]
+        public void Decimal(string inputString, int radix, int expectedResult)
+        {
+            var actualResult = XLWorkbook.EvaluateExpr($"DECIMAL(\"{inputString}\", {radix})");
+            Assert.AreEqual(expectedResult, actualResult);
+        }
+
+        [Test]
+        public void Decimal_ZeroIsZeroInAnyRadix([Range(2, 36)] int radix)
+        {
+            Assert.AreEqual(0, XLWorkbook.EvaluateExpr($"DECIMAL(\"0\", {radix})"));
+        }
+
+        [Theory]
+        public void Decimal_ReturnsErrorForRadiansGreater36([Range(37, 255)] int radix)
+        {
+            Assert.Throws<NumberException>(() => XLWorkbook.EvaluateExpr($"DECIMAL(\"0\", {radix})"));
+        }
+
+        [Theory]
+        public void Decimal_ReturnsErrorForRadiansSmaller2([Range(-5, 1)] int radix)
+        {
+            Assert.Throws<NumberException>(() => XLWorkbook.EvaluateExpr($"DECIMAL(\"0\", {radix})"));
+        }
+
         [Test]
         public void Floor()
         {