Here's an example of a study that used two of the DRSC small libraries. These libraries have an optimal layout (limits edge effects) and average 2 or more unique dsRNAs per gene.
Garcia MA, Alvarez MS, Sailem H, Bousgouni V, Sero J, Bakal C. Differential RNAi screening provides insights into the rewiring of signalling networks during oxidative stress. Mol Biosyst. 2012 Oct;8(10):2605-13. PMID: 22790786.