Posting again! Thanks.
> The name "SCHLAEGEL might be spelled SCHLAGEL", here in the U.S. they
spelled it
Try to write to the registry office of Oldenburg city. You should do it in German language and add your full postal address.
Send also the address where this family lived in Oldenburg, street etc.
The email address of the registry office is: standesamt@stadt-oldenburg.de
Good luck,
Werner Honkomp