Ecclesiastica Officia (diff. editions). -> Caput LXXX. De bibere post Vesperas.

Rituale cisterciense... Parisiis 1689. -> Lib. IV, cap. IX: De Bibere post Vesperas.

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Jalloutz, Dorothée / Vernet, Placide [ed.]: Cisterciens au Val-des-Choux et à Sept-Fons... Paris 2005. -> many mentions of "biberes" with commentaries.