1. Niall R. Whitty, ‘Indirect Enrichment in Scots Law’, [1994] Juridical Review 200–29, 239–82
2. Reinhard Zimmermann, The Law of Obligations: Roman Foundations of the Civilian Tradition (1996), chap. 26, 834–901
3. Reinhard Zimmermann, ‘Unjustified Enrichment: The Modern Civilian Approach’, (1995) 15 Oxford JLS 403–29
4. Dirk A. Verse, Verwendungen im Eigentümer-Besitzer-Verhältnis (1999)
5. Konrad Zweigert and Hein Kötz, An Introduction to Comparative Law (trans. Tony Weir, 3rd edn, 1998), chaps. 38 and 39, 537–94