Civil Law Act (Cap. 43): Primary legislation governing contractual relationships and obligations in Singapore, including requirements for valid contracts.

Sale of Goods Act (Cap. 393): Regulates the sale of goods, defines rights and obligations of buyers and sellers, and establishes implied terms and conditions in sales contracts.

Conveyancing and Law of Property Act (Cap. 61): Establishes requirements for property transactions, legal formalities for transfer of title, and requirements for execution of deeds.

Stamp Duties Act (Cap. 312): Governs stamp duty obligations, including timing and payment requirements for property transactions and legal documents.

Electronic Transactions Act (Cap. 88): Provides legal framework for electronic transactions and digital signatures, relevant if electronic execution is considered.

Singapore Contract Law: Common law principles governing contracts, including offer and acceptance, consideration, and capacity to contract.

Registration of Deeds Act (Cap. 269): Sets out requirements and procedures for the registration of legal instruments and deeds in Singapore.

Rules of Court: Establishes procedural requirements and guidelines for legal proceedings in Singapore courts if litigation arises.

Singapore Law Society Guidelines: Professional guidelines and standards for legal practitioners in Singapore regarding document preparation and execution.

Monetary Authority of Singapore Regulations: Regulatory requirements that may apply to certain types of sale and purchase transactions, particularly in regulated industries.