Schematron using XPath 2.0 PROC:error:Input_Product.child_check: proc:Input_Product class must contain at least 1 attribute or class. PROC:error:Process.child_check: proc:Process class must contain at least 1 attribute or class. PROC:error:Software.child_check: proc:Software class must contain at least 1 attribute or class. PROC:error:Software_Program.child_check: proc:Software_Program class must contain at least 1 attribute or class. PROC:error:input_product_reference_type_check: pds:reference_type must have value 'data_to_input_product' PROC:error:local_reference_type_check: pds:local_reference_type must have value 'processing_information_to_data_object' PROC:error:software_reference_type_check: pds:reference_type must have value 'data_to_software'