00286nam a2200109 a 450000500170000002000150001708200190003210000060005124500590005726000450011630000150016120251203110045.0  a8173192497  a621.38153bWAT  d_  aBasic training ISDNbintroduction to practical aspects  aNew DelhibNarosa Publishing Housec1998  a72p.c26cm