1. Ginj, M. et al. Synthesis of trifunctional somatostatin based derivatives for improved cellular and subcellular uptake. Tetrahedron Letters 2005, 46 (16), 2821-2824. 2. Dijkgraaf, I. et al. Synthesis of DOTA-conjugated multivalent cyclic-RGD peptide dendrimers via 1,3-dipolar cycloaddition and their biological evaluation: implications for tumor targeting and tumor imaging purposes. Organic & Biomolecular Chemistry 2007, 5 (6), 935-944. 3. Roosenburg, S. et al. Stabilized 111In-Labeled sCCK8 Analogues for Targeting CCK2-Receptor Positive Tumors: Synthesis and Evaluation. Bioconjugate Chem. 2010, 21 (4), 663-670