Jaro-Winkler string similarity implementation in (different) languages.
Notice: Only PHP for now.
Theoretical stuff can be found in: Winkler, W. E. (1999). "The state of record linkage and current research problems". Statistics of Income Division, Internal Revenue Service Publication R99/04. http://www.census.gov/srd/papers/pdf/rr99-04.pdf.
Literature references: This implementation is the same as the one from http://www.iugrina.com/files/JaroWinkler/JaroWinkler.phps which was referenced in Expert PHP and MySQL: Application Design and Development.