3LLN:
reference: Comparison between the orthorhombic and tetragonal forms of the heptamer sequence d[GCG(xT)GCG]/d(CGCACGC)., Robeyns K, Herdewijn P, Van Meervelt L, Acta Crystallogr Sect F Struct Biol Cryst Commun. 2010 Sep 1;66(Pt, 9):1028-31. Epub 2010 Aug 26. PMID: 20823518

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