Written arguments are submitted to the trial court, after completion of the evidence, as per the provisions of Section 314 Cr.P.C., which is reproduced as under:
“314. Oral arguments and memorandum of arguments.—(1) Any party to a proceeding may, as soon as may be, after the close of his evidence, address concise oral arguments, and may, before he concludes the oral arguments, if any, submit a memorandum to the Court setting forth concisely and under distinct headings, the arguments in support of his case and every such memorandum shall form part of the record.
(2) A copy of every such memorandum shall be simultaneously furnished to the opposite party.
(3) No adjournment of the proceedings shall be granted for the purpose of filing the written arguments unless the Court, for reasons to be recorded in writing, considers it necessary to grant such adjournment.
(4) The Court may, if it is of opinion that the oral arguments are not concise or relevant, regulate such arguments.”
There is no prescribed format for such written arguments. You can rely upon decided cases in these written arguments and mention a brief extract of the relevant legal principle decided in that case. If you so wish you can also provide copies of the relevant judgments reported in law journals on which you are relying.
You can quote opinion of the foreign writers who are experts in the field. Of course, you will have to show the relevant published book / opinion of such expert, if you want to rely on it.