' For complete examples and data files, please go to https://github.com/groupdocs-watermark/GroupDocs.Watermark-for-.NET
Using doc As Document = Document.Load(Utilities.MapSourceFilePath(DocFilePath))
Dim regex As New Regex("^© \d{4}$")
' Search by regular expression
Dim textSearchCriteria As New TextSearchCriteria(regex)
' Find possible watermarks using regular expression
Dim possibleWatermarks As PossibleWatermarkCollection = doc.FindWatermarks(textSearchCriteria)
End Using