diff --git a/src/Money.UI.Blazor/Pages/OverviewMonth.cs b/src/Money.UI.Blazor/Pages/OverviewMonth.cs
index 6b39aed8..d2455f34 100644
--- a/src/Money.UI.Blazor/Pages/OverviewMonth.cs
+++ b/src/Money.UI.Blazor/Pages/OverviewMonth.cs
@@ -13,30 +13,30 @@
 
 namespace Money.Pages
 {
-    [Route("/outcomes/{Year}/{Month}")]
-    [Route("/overview/{Year}/{Month}")]
-    [Route("/overview/{Year}/{Month}/{CategoryGuid}")]
-    [Route("/{Year}/{Month}/overview")]
-    [Route("/{Year}/{Month}/overview/{CategoryGuid}")]
+    [Route("/outcomes/{Year:int}/{Month:int}")]
+    [Route("/overview/{Year:int}/{Month:int}")]
+    [Route("/overview/{Year:int}/{Month:int}/{CategoryGuid:guid}")]
+    [Route("/{Year:int}/{Month:int}/overview")]
+    [Route("/{Year:int}/{Month:int}/overview/{CategoryGuid:guid}")]
     public class OverviewMonth : Overview<MonthModel>
     {
         [Parameter]
-        protected string Year { get; set; }
+        protected int Year { get; set; }
 
         [Parameter]
-        protected string Month { get; set; }
+        protected int Month { get; set; }
 
         [Parameter]
-        protected string CategoryGuid { get; set; }
+        protected Guid? CategoryGuid { get; set; }
 
         public OverviewMonth() 
             => SubTitle = "List of each single outcome in selected month";
 
         protected override MonthModel CreateSelectedItemFromParameters() 
-            => new MonthModel(Int32.Parse(Year), Int32.Parse(Month));
+            => new MonthModel(Year, Month);
 
         protected override IKey CreateSelectedCategoryFromParameters()
-            => Guid.TryParse(CategoryGuid, out var categoryGuid) ? GuidKey.Create(categoryGuid, KeyFactory.Empty(typeof(Category)).Type) : KeyFactory.Empty(typeof(Category));
+            => CategoryGuid != null ? GuidKey.Create(CategoryGuid.Value, KeyFactory.Empty(typeof(Category)).Type) : KeyFactory.Empty(typeof(Category));
 
         protected override IQuery<List<OutcomeOverviewModel>> CreateItemsQuery(int pageIndex) 
             => new ListMonthOutcomeFromCategory(CategoryKey, SelectedPeriod, SortDescriptor, pageIndex);
diff --git a/src/Money.UI.Blazor/Pages/OverviewYear.cs b/src/Money.UI.Blazor/Pages/OverviewYear.cs
index f3fa5764..71d0672c 100644
--- a/src/Money.UI.Blazor/Pages/OverviewYear.cs
+++ b/src/Money.UI.Blazor/Pages/OverviewYear.cs
@@ -13,24 +13,24 @@
 
 namespace Money.Pages
 {
-    [Route("/{Year}/overview")]
-    [Route("/{Year}/overview/{CategoryGuid}")]
+    [Route("/{Year:int}/overview")]
+    [Route("/{Year:int}/overview/{CategoryGuid:guid}")]
     public class OverviewYear : Overview<YearModel>
     {
         [Parameter]
-        protected string Year { get; set; }
+        protected int Year { get; set; }
 
         [Parameter]
-        protected string CategoryGuid { get; set; }
+        protected Guid? CategoryGuid { get; set; }
 
         public OverviewYear() 
             => SubTitle = "List of each single outcome in selected year";
 
         protected override YearModel CreateSelectedItemFromParameters()
-            => new YearModel(Int32.Parse(Year));
+            => new YearModel(Year);
 
         protected override IKey CreateSelectedCategoryFromParameters()
-            => Guid.TryParse(CategoryGuid, out var categoryGuid) ? GuidKey.Create(categoryGuid, KeyFactory.Empty(typeof(Category)).Type) : KeyFactory.Empty(typeof(Category));
+            => CategoryGuid != null ? GuidKey.Create(CategoryGuid.Value, KeyFactory.Empty(typeof(Category)).Type) : KeyFactory.Empty(typeof(Category));
 
         protected override IQuery<List<OutcomeOverviewModel>> CreateItemsQuery(int pageIndex)
             => new ListYearOutcomeFromCategory(CategoryKey, SelectedPeriod, SortDescriptor, pageIndex);
diff --git a/src/Money.UI.Blazor/Pages/SummaryMonth.cs b/src/Money.UI.Blazor/Pages/SummaryMonth.cs
index c481586d..8151957d 100644
--- a/src/Money.UI.Blazor/Pages/SummaryMonth.cs
+++ b/src/Money.UI.Blazor/Pages/SummaryMonth.cs
@@ -14,14 +14,14 @@
 namespace Money.Pages
 {
     [Route("/")]
-    [Route("/{Year}/{Month}")]
+    [Route("/{Year:int}/{Month:int}")]
     public class SummaryMonth : Summary<MonthModel>
     {
         [Parameter]
-        protected string Year { get; set; }
+        protected int? Year { get; set; }
 
         [Parameter]
-        protected string Month { get; set; }
+        protected int? Month { get; set; }
 
         public SummaryMonth() 
             => SubTitle = "Per-month summary of outcomes in categories";
@@ -36,8 +36,8 @@ protected override MonthModel CreateSelectedItemFromParameters()
         {
             Log.Debug($"CreateSelectedItemFromParameters(Year='{Year}', Month='{Month}')");
 
-            if (!String.IsNullOrEmpty(Year) && !String.IsNullOrEmpty(Month))
-                return new MonthModel(Int32.Parse(Year), Int32.Parse(Month));
+            if (Year != null && Month != null)
+                return new MonthModel(Year.Value, Month.Value);
             else
                 return null;
         }
diff --git a/src/Money.UI.Blazor/Pages/SummaryYear.cs b/src/Money.UI.Blazor/Pages/SummaryYear.cs
index c67004f1..29b1c58e 100644
--- a/src/Money.UI.Blazor/Pages/SummaryYear.cs
+++ b/src/Money.UI.Blazor/Pages/SummaryYear.cs
@@ -13,11 +13,11 @@
 
 namespace Money.Pages
 {
-    [Route("/{Year}")]
+    [Route("/{Year:int}")]
     public class SummaryYear : Summary<YearModel>
     {
         [Parameter]
-        protected string Year { get; set; }
+        protected int? Year { get; set; }
 
         public SummaryYear() 
             => SubTitle = "Per-year summary of outcomes in categories";
@@ -29,8 +29,8 @@ protected override YearModel CreateSelectedItemFromParameters()
         {
             Log.Debug($"CreateSelectedItemFromParameters(Year='{Year}')");
 
-            if (!String.IsNullOrEmpty(Year))
-                return new YearModel(Int32.Parse(Year));
+            if (Year != null)
+                return new YearModel(Year.Value);
             else
                 return null;
         }