How can I reference two field without nid or uid?
enable  entity reference module.
In the second CT , add an entity reference field.
In the field settings of the entity reference field select the first CT from a list of CT .
Create a view of second CT with all its related field.
Add relationship under the advanced options  ,  add an entity reference relationship referencing first CT.
Then add all the fields of first CT.
use the module link -
https://drupal.org/project/views_dependent_filters
for equating the serial text field.