<project>
  <modelVersion>4.0.0</modelVersion>
  <parent>
    <groupId>org.apache</groupId>
    <artifactId>apache</artifactId>
    <version>18</version>
  </parent>
  <groupId>org.apache.maven.ci</groupId>
  <artifactId>ci-parent</artifactId>
  <name>First CI Friendly</name>
  <version>${revision}</version>
  ...
  <properties>
    <revision>1.0.0-SNAPSHOT</revision>
  </properties>
  <modules>
    <module>child1</module>
    <module>child1</module>
    ..
  </modules>
</project>


<project>
  <modelVersion>4.0.0</modelVersion>
  <parent>
    <groupId>org.apache.maven.ci</groupId>
    <artifactId>ci-parent</artifactId>
    <version>${revision}</version>
  </parent>
  <groupId>org.apache.maven.ci</groupId>
  <artifactId>ci-child</artifactId>
   ...
  <dependencies>
    <dependency>
      <groupId>org.apache.maven.ci</groupId>
      <artifactId>childDep</artifactId>
      <version>${project.version}</version>
    </dependency>
  </dependencies>
</project>

<project>
  <modelVersion>4.0.0</modelVersion>
  <parent>
    <groupId>org.apache.maven.ci</groupId>
    <artifactId>ci-parent</artifactId>
    <version>1.0</version>
  </parent>
  <groupId>org.apache.maven.ci</groupId>
  <artifactId>ci-child</artifactId>
   ...
  <dependencies>
    <dependency>
      <groupId>org.apache.maven.ci</groupId>
      <artifactId>childDep</artifactId>
      <version>${project.version}</version>
    </dependency>
  </dependencies>
</project>