1. Z3str2 String Constraint Solver. https://sites.google.com/site/z3strsolver/
2. IBM Security AppScan Source. http://www-03.ibm.com/software/products/en/appscan-source
3. Kausler Suite. https://github.com/BoiseState/string-constraint-solvers
4. LibStranger. https://github.com/vlab-cs-ucsb/LibStranger
5. Personal communications with the Stranger team. 2015