diff --git a/xls/record/format.go b/xls/record/format.go
index fe1ad8f..bbd2384 100644
--- a/xls/record/format.go
+++ b/xls/record/format.go
@@ -10,6 +10,12 @@ import (
 	"strings"
 )
 
+const (
+	DefaultDateFormat            = "DD/MM/YYYY"
+	DefaultTimeFormat            = "hh:mm"
+	DefaultTimeFormatWithSeconds = "hh:mm:ss"
+)
+
 //FORMAT: Number Format
 
 var FormatRecord = []byte{0x1E, 0x04} //(41Eh)
@@ -107,8 +113,14 @@ func (r *Format) GetFormatString(data structure.CellData) string {
 				return fmt.Sprintf("%.f", data.GetFloat64())
 			} else {
 				t := helpers.TimeFromExcelTime(data.GetFloat64(), false)
-				dateFormat := strings.ReplaceAll(r.String(), "HH:MM:SS", "hh:mm:ss")
-				dateFormat = strings.ReplaceAll(dateFormat, "\\", "")
+				dateStringReplacer := strings.NewReplacer(
+					"dd/MM/yyyy", DefaultDateFormat,
+					"HH:mm", DefaultTimeFormat,
+					"HH:MM:SS", DefaultTimeFormatWithSeconds,
+					"\\", "",
+				)
+				dateFormat := dateStringReplacer.Replace(r.String())
+
 				return fmtdate.Format(dateFormat, t)
 			}
 
diff --git a/xls/record/labelSst.go b/xls/record/labelSst.go
index dd468a3..2ff0830 100644
--- a/xls/record/labelSst.go
+++ b/xls/record/labelSst.go
@@ -40,7 +40,13 @@ func (r *LabelSSt) GetCol() [2]byte {
 }
 
 func (r *LabelSSt) GetString() string {
-	return r.sst.Rgb[helpers.BytesToUint32(r.isst[:])].String()
+	number := helpers.BytesToUint32(r.isst[:])
+
+	if int(number) < len(r.sst.Rgb) {
+		return r.sst.Rgb[number].String()
+	}
+
+	return ""
 }
 
 func (r *LabelSSt) GetFloat64() (fl float64) {
@@ -58,9 +64,6 @@ func (r *LabelSSt) GetXFIndex() int {
 	return int(helpers.BytesToUint16(r.ixfe[:]))
 }
 
-
-
-
 func (r *LabelSSt) Read(stream []byte, sst *SST) {
 	r.sst = sst
 	copy(r.rw[:], stream[:2])