Rod Johnson: Spring Reference,
The Hibernate Team, The JBoss Vistual Design Team: Hibernate Reference Documentation: http://docs.jboss.org/hibernate/orm/4.1/manual/en-US/html/.
Martin Fowler: The Dependency Injection Pattern, http://www.martinfowler.com/articles/injection.html.
Ben Collins-Sussman: Version Control with Subversion, http://svnbook.red-bean.com/.
Apache Project: Maven guides, http://maven.apache.org/guides/index.html.
Alex Garrett: JUnit Anti-Patterns, http://www.ibm.com/developerworks/opensource/library/os-junit/.