Alaska Statutes Title 36. Public Contracts § 36.90.260. Miscellaneous provisions

(1) a payment is considered to be made when mailed or personally delivered to the party being paid;

(2) a payment is considered to be received when it is endorsed for payment, if it is a check;

(3) an invoice is considered to be received when it is date-stamped or otherwise marked as delivered; if the invoice is not date-stamped or otherwise marked as delivered, the date of the invoice is considered to be the date when the invoice is received.