Question: What are the distinct cross reference source system codes which are related to the master customer details 'Gottlieb, Becker and Wyman'?
Schema: create table customer_master_index (master_customer_id varchar, cmi_details varchar, PRIMARY KEY (master_customer_id)); create table cmi_cross_references (source_system_code varchar, master_customer_id varchar, PRIMARY KEY (source_system_code))
SQL: 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 = 'gottlieb ,  becker and wyman'