- A -

AE – Encyclopedias

AG – Dictionaries and Other General Reference Works

AI  – Indexes

AM – Museums.   Collector and Collecting

AN – Newspapers

AP – Periodicals

AS – Acedem ies and Learned Societies

AY – Yaerbooks, Almanacs, Directories

    - B -

B   – Philosophy (General)

BF – Psychology

BL – Religions.  Mythology.  Rationalism

BP – Islam.   Bahai Faith.   Theosophy, etc.

BX – Christian Denominations 

  - C -

CB – History of Civilization

CC – Arcaeology

CD – Diplomatics.   Archives.  Seals.

CS – Genealogy

CT – Biography

      - D -

D   – History (General)

DA - History of  Great Britain

DC - History of France

DG - History of Italy

DK - History of Russia. Soviet Union. Former Soviet Republics

DP – History of Spain

DR – History of Balkan Peninsula

DS – History of Asia

DT – History of Africa

      - E -

E – History: America   

      - F -

F - United States Local History

  - G -

G   – Geography (General)

GE – Environmental Sciences

GN – Anthropology

GR – Folklore

GT – Manners and Customs (General)

GV – Recreation. Leisure   

  - H -

H   – Social Sciences (General)

HA – Statistics

HB – Economic Theory .  Demography

HC – Economic History and Conditions

HD – Industries. Land use. Labor

HE – Transportation and Communications

HF – Commerce

HG – Finance

HJ – Public Finance

HM – Sociology (General)

HQ – The Family. Marriage. Woman

HS – Societies: Secret, Benevolent, etc.

HT – Communities.  Classes.  Races

HV – Social Pathology.  Social and Public Welfare.  Criminology

      - J -

JA – Political Science (General)

JC – Political Theory

JF-   Political Institutions and Public Administration

JQ – Political Institutions and Public Administration

JS – Local Government. Municipal Government

JX – International Law (see KZ)

JZ – International Relations  

  - K -

K     – Law in general. Comparative and Uniform Law. Jurisprudence

KKX – Law – Turkey

- L -

L   – Education (General)

LB – Theory and Practice of Education

LF – Individual Institutions

  - M -

M   – Music

ML – Literature on Music

    - N -

N   – Visual Arts

NA – Architecture

NC – Drawing.  Design.  Illustration

NK – Decorative Arts

NX – Arts in General

    - P -

P   – Philology. Linguistics

PC – Romanic

PE – English

PF – West Germanic. Deutch

PG – Slavic. Baltic. Albanian

PH – Uralic. Basque

PJ – Oriental Philology and Literature

PL – Languages of Eastern Asia, Africa, Oceania

PN – Literature (General)

    - Q -

Q    – Science (General)

QA – Mathematics-Computer-Statistics

QB – Astronomy

QC – Physics

QD – Chemistry

QE – Geology

QH – Natural History (General)

QK – Botany

QL – Zoology

QM – Human Anatomy

QP – Physiology

    - R -

R   – Medicine (General)

RA – Public Aspects of Medicine

RB – Pathology

RC – Internal Medicine

RD – Surgery

RJ – Pediatrics

RK – Dentistry

RL – Dermatology

RM – Therapeutics. Pharmacology

RS – Pharmacy and Materia Medica

RT – Nursing  

  - S -

S   – Agriculture (General)

SB – Plant Culture

SD – Forestry

SF – Animal Culture

    - T -

T   – Technology (General)

TA – Engineering (General), Civil Engineering

TC – Hydraulic Engineering

TD – Environmental Technology. Sanitary

TK – Electrical Engineering. Electronics. Nuclear Engineering.

TL – Motor Wehicles.  Aeronautics.  Astronautics

TN – Mining Engineering. Metallurgy

TP – Chemical Technology

TR – Photography

TS – Manufactures

TX – Home Economics 

  - U -

U   – Military Science (General)

UA – Armies: Organization, Distribution, Military Situation

  - V -

VK – Navigation. Merchant Marine

  - Z -

Z   – Books (General), Writing, Paleography