What are the classes involved in Journal in MSD axapta,

 What are the classes involved in Journal Posting, Sales Order Invoice Posting, Purchase Order Invoice posting,

1) Journal Posting : LedgerJournalCheckPost class

‎2). Sales Order Posting : SalesFormLetter Class and SalesFormLetter_Invoice class

3). Purchase Order Posting : involPurchFormLetter,Purch​FormLetter_PurchOrder,Purc​hFormLetter_Receiptlist,Pu​rchFormLetter_PackingSlip and PurchFormLetter_Invoice classes are involved.