Xref

Xref is also listed under the following categories: Standard Yellow Pages Heading (SYPH) Categories:

• Book Dealers Encyclopedias
• Publishers

North American Industry Classification System (NAICS) Categories:

• Book Stores > Book Dealers - Reference Materials > Book Dealers Encyclopedias
• All Other Publishers

Standard Industry Classification (SIC) Categories:

• Miscellaneous Publishing
• Book Stores > Book Dealers - Reference Materials > Book Dealers Encyclopedias