The Record’s Underlying Structure (cont.)
•600:  10 : Garreau, Joel. 
•651:   0 : United States|xDescription and travel|y1960- 
•651:   0 : United States|xEconomic conditions|y1961- 
•651:   0 : United States|xSocial conditions|y1960- 
•651:   0 : Canada|xDescription and travel|y1945- 
•651:   0 : Canada|xEconomic conditions|y1945- 
•651:   0 : Canada|xSocial condition. 
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•
… and this would be the continuation of the underlying structure.  Can you pick out the subfields?