........ Cell ular ▁tele phone ▁services ▁industry . ▁W ire less ▁tele phone ▁industry ▁ 9 7 1 9 - 9 7 2 1 ........ Art ific ial ▁satellite ▁tele communic ations ▁ 9 7 2 3 - 9 7 3 7 ........ Sign aling ▁ 9 7 5 1 - 9 7 5 6 ........ M essen ger ▁service ▁ 9 7 6 1 - 9 9 0 0 ........ A ir ▁transport ation . ▁Airlines ▁ ▁H F ▁- ▁Com merce ▁▁▁ 1 - 6 1 8 2 ........ .... ... Com merce ▁ 2 9 4 - 3 4 3 ........ ..... Bo ards ▁of ▁trade . ▁Ch amb ers ▁of ▁commerce . ▁Mer ch ants ' ▁associations ▁ 1 0 1 4 ................ Bal ance ▁of ▁trade ▁ 1 0 2 1 - 1 0 2 7 ........ ... Com mer cial ▁ge ography . ▁Econom ic ▁ge ography ▁ 1 0 4 0 - 1 0 5 4 ........ ... Com mod ities . ▁Com mer cial ▁products ▁ 1 7 0 1 - 2 7 0 1 ........ ... T ar iff . ▁Free ▁trade . ▁Prote ction ism ▁ 3 0 0 0 - 4 0 5 5 ........ ... By ▁region ▁or ▁country ▁ 5 0 0 1 - 6 1 8 2 ........ ... Bus iness ▁ 5 3 8 1 - 5 3 8 6 ........ .. V oc ational ▁Gu id ance . ▁Career ▁development ▁ 5 3 8 7 - 5