Found 2 books

Practical Asterisk 1.4 & 1.6

[en] Practical Asterisk 1.4 & 1.6 Addison-Wesley Professional

Wintermeyer, Stefan & Bosch, Stephen

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Practical Asterisk 1.4 and 1.6 · From Beginner to Expert

[en] Practical Asterisk 1.4 and 1.6 · From Beginner to Expert Addison-Wesley Professional

Wintermeyer, Stefan & Bosch, Stephen

download read it!