PC Software workbook ; A tutorial introduction to: The PC and DOS ; PC-Write TM ; PC-Calc+TM ; PC-File+TM / James A. O'brien, John W. Durham. -- 2nd ed. -- Homewood-Illinois : IRWIN Inc., 1989. -- 239 s. -- obr. + 7 diskiet. programy počítačové * PC-Write * PC-Calc+ * PC-File