Eric,

The default Service Level for WorldCat Search API doesn't include the
Library of Congress Call number (050)

However, you can make this type of request at the full Service Level
and get this information.

For example

http://www.worldcat.org/webservices/catalog/content/55679231?wskey=[yourkey]&servicelevel=full

When you do that you'll get you a MARCXML record that includes the 050.

FYI - the example OCLC Number you provided doesn't have a Library of
Congress call number.

Please note that there are rules about when an application can use the
full Service Level -
http://www.oclc.org/developer/documentation/worldcat-search-api/service-levels

Karen

On Tue, Jul 17, 2012 at 10:09 AM, Reese, Terry
<[log in to unmask]> wrote:
> You'd likely want to use the classify service if all you needed was a call number.  It's a different API -- but the one MarcEdit has made use of for the past 2 1/2 years to provide folks with batch call number insertion in either LC or Dewey.
>
> --tr
>
> -----Original Message-----
> From: Code for Libraries [mailto:[log in to unmask]] On Behalf Of Eric Lease Morgan
> Sent: Tuesday, July 17, 2012 8:07 AM
> To: [log in to unmask]
> Subject: Re: [CODE4LIB] worldcat api
>
>> If so, then given an OCLC number is it possible get an LCCN ^h^h^h^ Library of Congress call number, and if so, then how?
>
> Oops! I know I can get an LCCN. Given an OCLC number, what I need is a Library of Congress call number. --Earache