How to put text align center before the Bibliography

Hi,

I have a code here that Insert a text before the Bibliography field but the problem is the first text in the bibliography field

please refer to the picture to see my problem

and this is what I want to happen

the text reference is in the center while all the bibliography source are in the left alignment

I hope someone will help me about this

by the way here's the code

Microsoft.Office.Interop.Word.Application aApplication = Globals.ThisAddIn.Application;
                Range rng = aApplication.Selection.Range;
                aApplication.Selection.EndKey(ref paramWdUnits, ref paramWdMovementType);
                aApplication.Selection.InsertBreak(WdBreakType.wdLineBreak);
                aApplication.Selection.InsertBreak(WdBreakType.wdLineBreak);
                aApplication.Selection.Fields.Add(wordApplication.Selection.Range,
                ref paramWdFieldTypeBiblio, ref paramMissing, ref paramMissing);
                rng.InsertAfter("Reference");
                rng.Font.Bold = -1;
                rng.Font.Size = 20;
                rng.ParagraphFormat.Alignment = Microsoft.Office.Interop.Word.WdParagraphAlignment.wdAlignParagraphCenter;

Thank you in advance

More Power

God Bless