Houghton Library uses a variety of local classifications schemes, some inherited from other Harvard libraries, others devised in-house.
Historically, asterisks were included at the front and back of many Houghton call numbers (to distinguish them in the union card catalog); this is no longer being done. When a cataloger finds a call number containing an asterisk, that asterisk should be removed.
Also historically, many Houghton call numbers had their size designation at the end of the call number. To manage electronic files such as Aleph and Aeon, size designations have been moved to the front of all call numbers (subfield "c" in the 852). If a cataloger should find a size designation at the end of a call number, it should be moved to subfield "c".