Source and Workbook

Source noun - A point or place at which something is invented or provided.

Workbook and source are semantically related In some cases you can use "Workbook" instead a noun "Source".

Workbook noun - A student's book or booklet containing problems with spaces for solving them.

Source and workbook are semantically related in book used in education topic. Sometimes you can use "Source" instead a noun "Workbook".