The energy input required for gas compression depends on the thermodynamic path taken (such as isothermal versus adiabatic), as governed by basic thermodynamic laws. No citation is needed for this well-established physical principle.
The claim compares the energy requirements of isothermal and adiabatic gas compression processes, which is a fundamental and uncontroversial tenet of classical thermodynamics (involving differing work integrals due to heat transfer). Per the instructions, statements that are trivially true by definition or direct application of established physical laws are classified as common knowledge, requiring no formal citation.