Programming Grails

Programming Groovy 2

The Definitive Guide to Grails 2

Gradle in Action

Grails

Beginning Groovy, Grails and Griffon

Grails Persistence with GORM and GSQL

Gradle Beyond the Basics

Groovy Recipes

Grails 2: A Quick-Start Guide

Programming Groovy

Groovy 2 Cookbook

Making Java Groovy