Dark Energy in the Universe

I 24 Studying the Nature of Dark Energy with Galaxy Clusters I 50 Constraining Dark Energy via Baryon Acoustic Oscillations I 65 Constraining Dark Energy with Redshift Surveys I 103 Dark Energy: Necessity, Models and Expectations I 177 Searching for galaxy clusters through weak lensing, X‐rays and the SZ observations I 181 SNIa and Dark Energy