pre-requisites for a union

Question

Pre-requisites for a Union Catalogue 

Compilation of a union catalogue is possible only through library cooperation. Any such compilation should be very clear in the beginning itself about the 

1. purpose of the Union catalogue to be compiled, 
2. region to be covered, 
3. materials to be covered; (decision as to the type of reading materials,  language, period, subject, etc), 
4. physical form of the catalogue,  
5. catalogue code to be followed, 
6. type of entries, 
7. level of description, 
8. arrangement of entries, and 
9. The method of compilation and revision.