000  $anz n  2
000  $a주제어
001  $aKSH1998001192
005  $a19980429124941
008  $a980429 n azknnaabn          |a a|a    | 
150  $aPU 4
450  $wr$i영어$aphysical unit 4
550  $wg$a시스템 네트워크 구조[--構造]
550  $aPU 2
550  $aPU 2.1
550  $aPU 5
550  $aPU(네트워크)