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* Federal Government Resources: Call numbers for U.S. government publications
A selected topical bibliography of U.S. Federal government information sources primarily but not exclusively located on the WWW.
Chart of SuDoc Classification and Library of Congress (LC) Classification Numbers
Differences between SuDoc and LC Numbers
The item on the left above is a federal publication titled "Forum." It is a journal for English teachers published by the Educational and Cultural Bureau of the Department of State.
The item on the right is a book written by T. Swann Harding called "Two Blades of Grass." It is a history of agricultural development.
As you can see, the items are very different and would not logically be shelved near each other. This is because the "S" stem in SuDoc is used by the Department of State and the "S" stem in LC is used for items on agriculture. There are many places where LC and SuDoc use the same stem, so here are a few tips for identifying these items and telling the formats apart.
Look for a "government publication" or "government collection" sticker (see below). Most federal publications have one.
Look for colons and slashes. LC does not use this punctuation; however SuDoc uses it very often. It is the best way to tell them apart.
Look near the back of the book or on the title page. If it says it was distributed through the Government Publishing Office (GPO), it is most likely a federal publication -- the exception to this are titles that are cataloged and housed in the main collection. If it says "GPO" it is a federal publication but might be housed and labeled as LC. The same holds true for items published by government agencies, but not distributed by the GPO.
Check the online catalog InfoKat. Most recent titles on a topic are often published by U.S. Government agencies.
Sometimes the alignment of the call number or frequency of letters or punctuation can give a strong indication as to which format the book is, as shown above.