Anh
direct surface
primary surface
Đức
Grundflaeche
Primaerheizflaeche
Pháp
surface directe
surface primaire
surface directe,surface primaire /SCIENCE,ENG-MECHANICAL/
[DE] Grundflaeche; Primaerheizflaeche
[EN] direct surface; primary surface
[FR] surface directe; surface primaire