(1) If a will mentions another document and raises a question whether the document does or does not form part of the will, the applicant must produce the other document or, if possible, explain its absence.
(2) The court must not include in a grant a document mentioned in a will unless it appears to the court to have been in existence when the will was made.
(3) If there is any evidence supporting the inference that any paper may have been attached to the will, the applicant must produce the paper or, if possible, explain its absence.