Classification
PLA - Astrosciences - general
18
AHZ - History of science and technology
3
TKH - Air flight, space flight
3
PEG - Optics
2
YZA - Politics, political science
2
AAE - Popular science - general aspects
1
AHQ - Art and exhibitions
1
AMA - Education - general
1
GRAD - Earth atmosphere, weather
1
MWA - Probability theory - general
1
MWF - Programming, optimization, control theory
1
PAE - Physics - general interest
1
PGA - Plasma physics
1
PKA - Elementary particles, nuclei - general
1
PKC - Elementary particles, nuclei - general theory
1
TGH - Technical optics
1
TNW - Nuclear controversy
1