--- /dev/null
+<?php
+
+namespace pq\Mapper;
+
+interface RefPropertyInterface extends PropertyInterface
+{
+ /**
+ * @param string $class
+ */
+ function to($class);
+
+ /**
+ * @param string $class
+ * @return bool
+ */
+ function references($class);
+
+ /**
+ * @param string $ref
+ */
+ function by($ref);
+
+ /**
+ * @param string $ref
+ * @return bool
+ */
+ function on($ref);
+}