Supporting References enables users to enter additional information for the journal entry header and lines that can be used for analytical purposes. This functionality was earlier known as Analytical Criteria. This enhancement was released in R12.0.3.
Business Benifits of Supporting references may be used as follows:

• To provide additional business information about a subledger journal entry at the header or line level
• To establish a subledger balance for a particular source value or combination of source values for a particular account
• To assist with reconciliation of account balances, and
• For financial and managerial analysis

The use of supporting references is optional, consist of these steps in order to use.

1. Define a Supporting Reference
2. Attach the Supporting Reference to the Journal Line Type (JLT)
3. Validate the Applications Accounting Definitions

In R11i, additional data was interfaced to GL on the journals using Descriptive Flexfields where as R12 With this, customers can create customized sources as Supporting References and pass values into those sources from Subledgers like AP/AR/PA etc. Supporting references (SR) are associated at the Event Class Level. These SRs are stored in XLA_AE_LINE_ACS and associated using ae_header_id/ae_line_num. This helps link back to XLA_AE_LINES records.
From XLA_AE_LINES, the link to GL is using GL_SL_LINK_ID and GL_SL_LINK_TABLE
For setup of Supporting References, there are 3 options

• Always: Supporting Reference Balances are maintained always on a specific Code Combination and it keeps on accumulating once it is defined. At the end of a Financial Period, the balances are carried forward as the opening balances for the next financial period.
• Based on Account: Supporting Reference Balances are maintained on a specific Code Combination & it gets accumulated till the end of a financial period. The closing balances of a Financial Period are not carried forward as the opening balances of the next financial period; rather the balance is rolled back to zero (0) at the beginning of the next financial period.
• Never: Supporting Reference Balances are not maintained for that Supporting Reference, it is only used as an additional reference attribute.
  When the Create Accounting program is run in the “Final” mode for any subledger, it spawns the program “Update Subledger Balances” internally and the balances are updated in the XLA_AC_BALANCES table.

Supporting References - What Tables for Analytical
Here are the list of table. If you have plan to do some custom reporting for Analytical for Opertional reporting you can understand the data model as per figure below.

• XLA_ANALYTICAL_ASSGNS
• XLA_ANALYTICAL_BALANCES
• XLA_ANALYTICAL_DTLS_B
• XLA_ANALYTICAL_DTLS_TL
• XLA_ANALYTICAL_DTL_VALS
• XLA_ANALYTICAL_HDRS_B
• XLA_ANALYTICAL_HDRS_TL
• XLA_ANALYTICAL_SOURCES
• XLA_EVENT_SOURCES

Supporting Refrence for Manual created Refrence
In R12, supporting references were introduced and the UI enables a user to However, the current version of manual journal creation API has not been supported to capture. Check it out with latest version of the code.