Innentitelbild: Natural Abundance 17O DNP NMR Provides Precise O−H Distances and Insights into the Brønsted Acidity of Heterogeneous Catalysts (Angew. Chem. 31/2017). (9th June 2017) - Perras, Frédéric A.; Wang, Zhuoran; Naik, Pranjali; Slowing, Igor I.; Pruski, Marek