Proposition 19
Tag 0546, permanent. Cite it as [Bourbaki, Tag 0546].
Commutative Algebra, chapter VII, § 4. Modules over integrally closed Noetherian domains
Let be a finitely generated -module. For to be reflexive, it is necessary and sufficient that be a reflexive -module.
We have remarked in the proof of Proposition 18 that for R to be a torsion-free B-module, it is necessary and sufficient that be a torsion-free A-module. We may therefore assume that R is a lattice of with respect to B. We shall use the following lemma:
Bourbaki puts the proof directly after the statement, so what is above is the statement and its proof together.