Practice Activity 8.2 Single entry in the accounting records of a business entity

Why is a schedule showing amounts owed by credit customers classified as a single entry?

See the suggested answer to practice activity 8.2 here.

Suggested answer to practice activity 8.2

A schedule showing amounts owed by credit customers are classified as a single entry because the schedule is not in journal or ledger form. There is no debit or credit side of the schedule. It is documentation of the amounts owed by different credit customers.

It is also a single entry because there is no identification in the schedule showing the other account (or corresponding entry) that should be debited or credited.