Classification
EXA - Energy policy
EWA - Energy economy
3
ETC - Energy conversion
2
EVB - Energy supply of Germany
2
EUA - Energy conservation - general
1
TED - Electric power - industrial aspect
1
TNA - Nuclear engineering - general
1
UED - Environmental policy
1
YPB - Economy - general aspects
1
YPM - National economy
1
YZA - Politics, political science
1