"A carrier who has paid compensation in compliance with the provisions of this Convention, shall be entitled to recover such compensation, together with interest thereon and all costs and expenses incurred by reason of the claim, from the other carriers who have taken part in the carriage, subject to the following provisions: (a) the carrier responsible for the loss or damage shall be solely liable for the compensation whether paid by himself or by another carrier."
"Carriers shall be free to agree among themselves on provisions other than those laid down in articles 37 and 38."