You can retrieve a complete set of MARC records for all of your subscriptions from LibCentral >see more
However, if you have access to multiple subscription collections and need MARC records for only one or a select few subscriptions, use these instructions:

1.  Go to your LibCentral site at: https://YOURSITE.ebookcentral.proquest.com/libcentral (where YOURSITE is your Ebook Central site identifier)
2.  Select the "Advanced Search" tool
3.  Under the "Collection" filter select the specific subscription collection name, then hit Search
4.  Click the "Export Results" option to retrieve the MARC record file

Note: If your selected set is over 5,000 records, it will only be available for email delivery, not direct download.