The tenderer and the winning bidder shall, within 30 days from the date of issuance of the bid-winning notice, conclude a written contract in accordance with the tender documents and the bid documents of the winning bidder. The tenderer and the winning bidder shall not conclude other agreements that deviate from the substantive contents of the contract. If the tender documents require the winning bidder to submit the performance bond, the winning bidder shall submit it. Article 490 of the Civil Code of People's Republic of China (PRC): If the parties conclude a contract in the form of a contract, the contract is concluded when the parties sign, seal or fingerprint it. Before signing, sealing or fingerprinting, one party has fulfilled its main obligations, and the contract is established when the other party accepts it. A contract shall be concluded in written form as stipulated by laws, administrative regulations or agreed by the parties. If the parties do not do this in writing, but one party has fulfilled its main obligations and the other party accepts it, the contract is established. Article 491 The parties entered into a contract in the form of data messages. It is also required to sign a confirmation letter, and the contract is established when the confirmation letter is signed. If the information of a commodity or service released by one party through information networks such as the Internet meets the conditions of the offer, the contract is established when the other party successfully selects the commodity or service and submits the order, unless otherwise agreed by the parties. Article 492 The place where the acceptance takes effect is the place where the contract is established. Where a contract is concluded in the form of a data message, the recipient's principal place of business is the place where the contract is established; If there is no main place of business, the domicile shall be the place where the contract is established. Unless otherwise agreed by the parties, such agreement shall prevail.