Steam distillation lowers the boiling point of immiscible organic compounds by vaporizing them at temperatures below their individual boiling points according to Dalton's law of partial pressures, representing a standard principle of chemistry that requires no citation.
The claim describes a fundamental, textbook physical chemistry principle (steam distillation and partial pressures) that is trivially true by definition and everyday scientific observation. None of the retrieved papers specifically test or evaluate this underlying thermodynamic law, but the statement itself is common knowledge in chemistry.