http://semver.org/ https://code.google.com/p/guava-libraries/wiki/RangesExplained http://maven.apache.org/enforcer/enforcer-rules/versionRanges.html http://docs.codehaus.org/display/MAVEN/Dependency+Mediation+and+Conflict+Resolution#DependencyMediationandConflictResolution-DependencyVersionRanges