ArticleTypeField::TypesConvertibleFrom PHP Method

    public static function TypesConvertibleFrom($p_type)
    {
        $allTypes = self::DatabaseTypes();
        if (!array_key_exists($p_type, $allTypes)) {
            return false;
        }
        $convertibleFromTypes = array();
        foreach ($allTypes as $typeName => $sqlDesc) {
            if (array_search($p_type, self::TypesConvertibleTo($typeName)) !== false) {
                $convertibleFromTypes[] = $typeName;
            }
        }
        return $convertibleFromTypes;
    }