The call numbers for material in the Main Library always begin with letters Hc
Second part of the call number is the floor where the material resides
Third part of the call number is the field of science the material belongs to (in Finnish)
Next part of the call number is the name of the shelf-class, which varies greatly depending on the field of science
Last part of the call number is the keyword, which is either the surname of the first author or the first word in the name of book if the book has only editors.
