Contracts are governed by the Federal Acquisition Regulations (FAR) which are uniform contract principles, terms and conditions that apply to all federal contracts. Each agency is allowed to supplement the FAR with agency-specific requirements. Therefore, in any contract you would expect to see a combination of clauses from the FAR and DEAR (Department of Energy); DFAR (Department of Defense); EPAAR (Environmental Protection Agency); etcetera, as the case may be. These agency regulations are required to go through a formal rule-making process so the public has an opportunity to comment. However, you will also see some clauses that agencies use that have internal numbers and that have not been published. These clauses normally address local administrative requirements of the agency; as, for example, where to send the invoice.
All contracts should have the same format as outlined in the FAR (sections A through J). There should always be a statement of work (SOW) that defines the work activities as an attachment in the J. section. Sections K, L, and M appear only in solicitations as they are specific instructions on certifications (K), preparation of the proposal (L), and evaluation criteria for the proposal (M). These sections drop off when the award is made.