Printers' Ink, Sep 16, 1915 (Vol. 92, No. 12): "Sales Letter Experiences with Two Million Customers" by Charles R. Wiers
The pattern
This still sits in the public-domain pool. No pattern name yet.
Why it works
Practical case histories of direct sales correspondence handling two hundred thousand customers. Demonstrating that empathetic letters resolve complaints and retain accounts trains customer service.
Steal this when
When training customer service teams to turn frustrated complaint letters into loyal repeat buyers.