Below is the list of tables from the database along with their columns and datatype. Need to generate an accurate SQL query for the question.
Only use the columns present in the respective table. Only use the columns which are required to generate the SQL query. Only use table joins if required and not otherwise.

### Tables ###
TABLE: CREATE TABLE table_name_38 ( isbn_uk VARCHAR, author VARCHAR, isbn_us VARCHAR )

### Question ###
What is ISBN UK, when Author is 'Dave Martin', and when ISBN US is 'N/A'?

### Accurate SQL ###

SELECT isbn_uk FROM table_name_38 WHERE author = "dave martin" AND isbn_us = "n/a"