on general ledger voucher transaction inquiry screen (General Journal > Inquiries and reports > Voucher transactions), there is a field already available called "Transaction type" which tells user the main source of the voucher which gets posted. (like Sales order, purchase order, production, inventory etc.)

if user wants to know the 'original document' reference of any voucher, he/she needs to make few clicks to reach to the original document e.g. sales order (1 by 1 for every voucher)

It will be very helpful to add 2 more column in the voucher transaction list grid i.e. 'Document type' and 'Document number' (from sub-ledger) which is/are responsible for the voucher entry in GL.

example:

Journal No. Voucher No. Transaction type Document type Document no.
JVT-197453 18965 Purchase order Purchase invoice PO # 123456
JVT-197454 20937 Sales order Sales invoice SO # 986675
JVT-197455 30865 Customer Free text invoice FTI # 675557