[UBL-SR-43-GST-SG]-AdditionalDocumentReference/DocumentTypeCode shall only be used for invoiced object (code 130), project reference in CreditNote (code 50) or total amounts including or excluding GST in SGD (code sgdtotal-incl-gst or sgdtotal-excl-gst)
UBL-SR-43-GST-SG
cac:AdditionalDocumentReference[cbc:DocumentTypeCode]
((cbc:DocumentTypeCode='130' or cbc:DocumentTypeCode='sgdtotal-incl-gst' or cbc:DocumentTypeCode='sgdtotal-excl-gst') or ((local-name(/*) = 'CreditNote') and (cbc:DocumentTypeCode='50')))