Chapter25 (v11) Integrating new collections: Integrating new sets and maps
Chapter26 (v1) Extractors
Chapter26 (v2) Extractors: An example: extracting email address
Chapter26 (v3) Extractors
Chapter26 (v4) Extractors: Patterns with zero or one variable
Chapter26 (v5) Extractors: Patterns with zero or one variable (source)