public function getSiblings($includeNode = true)
	{
		$parent = $this->getParent();
		$siblings = null;
		
		if ( ! is_null($parent)) {
			$siblings = $parent->getChildren();
		} else {
			$siblings = $this->repository->getRootNodes();
		}
		
		if ( ! $includeNode) {
			foreach ($siblings as $key => $sibling) {
				if ($sibling->isEqualTo($this)) {
					unset($siblings[$key]);
					break;
				}
			}
			// reset index
			$siblings = array_values($siblings);
		}
		
		return $siblings;
	}