The codebook used with the indicators AEFEA, CFIFC, DAEAD, DJDJD, EGBGE, HBJBH consists of 3000 different groups. These groups are constructed in the following way:

The code book is ordered according to the plain text words. For matter of convenience it is divided in several parts.
Choose the part containing all plain text words beginning with letters:

A - CU   CY - G   H - O   P - Z