diff --git a/GPW.CORE.Data/Controllers/GPWController.cs b/GPW.CORE.Data/Controllers/GPWController.cs
index 0c60519..7b2a011 100644
--- a/GPW.CORE.Data/Controllers/GPWController.cs
+++ b/GPW.CORE.Data/Controllers/GPWController.cs
@@ -47,17 +47,17 @@ namespace GPW.CORE.Data.Controllers
                 // recupero intero set dati timbrature e attività....
                 rawTimbExp = localDbCtx
                                 .DbSetTimbratureExpl
-                                .Where(x => x.IdxDipendente == idxDipendente && x.DataLav >= dtInizio && x.DataLav <= dtFine)
+                                .Where(x => x.IdxDipendente == idxDipendente && dtInizio <= x.DataLav && x.DataLav <= dtFine)
                                 .ToList();
 
                 rawTimbr = localDbCtx
                                 .DbSetTimbrature
-                                .Where(x => x.IdxDipendente == idxDipendente && x.DataOra >= dtInizio && x.DataOra <= dtFine)
+                                .Where(x => x.IdxDipendente == idxDipendente && dtInizio <= x.DataOra && x.DataOra <= dtFine)
                                 .ToList();
 
                 rawRegAtt = localDbCtx
                                 .DbSetRegAttivita
-                                .Where(x => x.IdxDipendente == idxDipendente && x.Inizio >= dtInizio && x.Inizio <= dtFine)
+                                .Where(x => x.IdxDipendente == idxDipendente && dtInizio <= x.Inizio && x.Inizio <= dtFine)
                                 .ToList();
 
                 // calcolo intervallo date...
diff --git a/GPW.CORE.Data/WeekData.cs b/GPW.CORE.Data/WeekData.cs
index 682c897..625d20b 100644
--- a/GPW.CORE.Data/WeekData.cs
+++ b/GPW.CORE.Data/WeekData.cs
@@ -37,7 +37,7 @@ namespace GPW.CORE.Data
         {
             this.anno = year;
             this.weekNumber = numWeek;
-            DateTime dtRif = new DateTime(year, 1, 4).AddDays(7 * numWeek);
+            DateTime dtRif = FirstDateOfWeekISO8601(year, numWeek);
             DayOfWeek day = CultureInfo.InvariantCulture.Calendar.GetDayOfWeek(dtRif);
             this.inizio = dtRif.Date.AddDays(1 - (int)day);
             this.fine = dtRif.Date.AddDays(7 - (int)day);
@@ -67,5 +67,32 @@ namespace GPW.CORE.Data
             // Return the week of our adjusted day
             return CultureInfo.InvariantCulture.Calendar.GetWeekOfYear(time, CalendarWeekRule.FirstFourDayWeek, DayOfWeek.Monday);
         }
+
+        public static DateTime FirstDateOfWeekISO8601(int year, int weekOfYear)
+        {
+            DateTime jan1 = new DateTime(year, 1, 1);
+            int daysOffset = DayOfWeek.Thursday - jan1.DayOfWeek;
+
+            // Use first Thursday in January to get first week of the year as
+            // it will never be in Week 52/53
+            DateTime firstThursday = jan1.AddDays(daysOffset);
+            var cal = CultureInfo.CurrentCulture.Calendar;
+            int firstWeek = cal.GetWeekOfYear(firstThursday, CalendarWeekRule.FirstFourDayWeek, DayOfWeek.Monday);
+
+            var weekNum = weekOfYear;
+            // As we're adding days to a date in Week 1,
+            // we need to subtract 1 in order to get the right date for week #1
+            if (firstWeek == 1)
+            {
+                weekNum -= 1;
+            }
+
+            // Using the first Thursday as starting week ensures that we are starting in the right year
+            // then we add number of weeks multiplied with days
+            var result = firstThursday.AddDays(weekNum * 7);
+
+            // Subtract 3 days from Thursday to get Monday, which is the first weekday in ISO8601
+            return result.AddDays(-3);
+        }
     }
 }