IBR-090
[ibr-090]-Only one project reference (ibt-011) is allowed on document level.
Targeted Semantic Element
    
        
        
        - IBT-011-Project reference
            :
            The identification of the project the invoice refers to
            
        
 
        
    
Schematron Rules
    
        
        
        
        
            - 
                
- IBR-090
 
             
            
                - Flag
 
                - fatal
 
                - Context
 
                /ubl:Invoice | /cn:CreditNote 
                - Message
 
                - [ibr-090]-Only one project reference (ibt-011) is allowed on document level.