Task: Text to Code
Input (English): Step 1: For each row in Customer_Master_Index table, find the corresponding rows in CMI_Cross_References table.
Step 2: find without repetition source_system_code of the results of step 1 whose cmi_details equals Gottlieb ,  Becker and Wyman and cmi_details equals Schmitt-Lang
Output (English): SELECT DISTINCT T2.source_system_code FROM Customer_Master_Index AS T1 JOIN CMI_Cross_References AS T2 ON T1.master_customer_id = T2.master_customer_id WHERE T1.cmi_details = "Schmitt-Lang" AND T1.cmi_details = "Gottlieb ,  Becker and Wyman"