Can someone please help me identify the entities for an extended entity
relationship diagram for the below scenario.

Thanks.

EmJ.

Better Books and Bargains

The book shop sells books,  which may be either fiction or non-fiction.
Books have an ISBN, bar-code, title, author(s) / editor(s), publisher, date
of publication, quantity in stock, price, quantity on order.
There  may be a series title.

Fiction books are either paperback, large paperback or hardback and may be
ranked in 'The Guardian' top 40 best seller list.

Non-fiction books belong to a subject area and may have an edition number.

Due to the expansion the shop now also sells other merchandise such as:
·       magazines which have a bar-code, title, and issue number and/or
date, publisher, price, quantity in stock, quantity on order.
·       stationery items with bar code, price, quantity in stock, quantity
on order, description, supplier.
·       greetings cards with bar-code, price, type, quantity in stock,
quantity on order, printer, description, supplier.
·       seasonal items with bar-code, price, quantity in stock, quantity on
order, supplier, start date, end date, description.

Customers make purchases for which they receive receipts having a receipt
number, date, quantity, bar-code, brief description, price and sales person
code.

Sometimes a special offer voucher may be offered in payment.  These will
have a voucher number, value, company of issue and expiry date.

The issue of a receipt causes the quantity in stock  to be updated.

The sales person code is used to calculate the monthly bonus.