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DNA targeting specificity of RNA-guided Cas9 nucleases (https://crispr.bme.gatech.edu/): Contains experimental data about the specificity. They also have a server based on the data.

A Biophysical Model of CRISPR/Cas9 Activity for Rational Design of Genome Editing and Gene Regulation: This is a simple biophysical model used to predict the specificity of the sgRNA based on the sequence. They split the process in 3 steps and add the free energy change of each process to calculate a binding energy.

High-fidelity CRISPR–Cas9 nucleases with no detectable genome-wide off-target effects : Mutations on residues that bind to the phosphate backbone of the DNA can improve the specificity.

Layman news:

https://www.wired.com/2017/06/crispr-mutations/

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