SQL Script for Oracle Receivables transactions and Credit notes

I have written the following SQL Script to retreive AR Invoice Information. It retrieves all the AR Invocie Transactions but will not retieve andy Credit Notes even though I can view them in the ra_customer_trx_all table which is my I have select below. Any help with this would be much appreciated

select

decode(a.set_of_books_id,21,'DHB Co3',22,'HPac exclGST Co2',1,'HPac inclGST Co2',41,'DOC Co4') "set_of_books",

a.trx_date,

a.trx_number,

k.description batch_description,

l.name batch_name,

a.complete_flag,

a.status_trx,

j.name terms,