//src/MSKIS/GlobalBundle/Entity/Source.php
     /**
     * @ORM\OneToOne(targetEntity="SourceGroup")
     * @ORM\JoinColumn(name="source_group_id", referencedColumnName="id") 
     */
    
    protected $sourceGroup;
    
    /**
     * @OneToOne(targetEntity="SourceType")
     * @JoinColumn(name="source_type_id", referencedColumnName="remote_id") 
     */
    protected $sourceType;


//src/MSKIS/GlobalBundle/Entity/SourceType.php
<?php

namespace MSKIS\GlobalBundle\Entity;

use Doctrine\ORM\Mapping as ORM;
use Symfony\Component\Validator\Constraints as Assert;

/**
 * @ORM\Entity
 * @ORM\Table(name="source_type")
 */
class SourceType {

    /**
     * @ORM\Id
     * @ORM\Column(type="integer")
     * @ORM\GeneratedValue(strategy="AUTO")
     */
    protected $id;

    /**
     * @ORM\Column(type="string", length="255") 
     * @Assert\MinLength(2)
     * @Assert\MaxLength(255)
     */
    protected $name;
    
}

?>