Robert Sedgewick, Kevin Wayne, Algorithms (4th Edition).

• Comprehensive introduction to string algorithms and data structures.

Dan Gusfield, Algorithms on Strings, Trees, and Sequences.

• In-depth coverage of string matching, subsequences, and related problems.

Wikipedia: String (computer science)

• https://en.wikipedia.org/wiki/String_(computer_science)
• Definitions, properties, and applications of strings.

Paul Zeitz, The Art and Craft of Problem Solving.

• Problem-solving strategies and string-based puzzles.

NPTEL: Data Structures and Algorithms

• https://nptel.ac.in/courses/106/106/106106127/
• Video lectures and notes on string algorithms and applications.