Understanding dBASE IV 1.5 for DOS / Alan Simpson. Simpson, Alan, 1953- Simpson, Alan, 1953- Understandind dBase IV 1.1. dBASE IV (Computer file) Database management. QA76.9.D3 S57433 1992 001.6424 20 SIU Rev. ed. of: Understanding dBase IV 1.1. 2nd ed. c1989. Includes index. San Francisco : Sybex, New Delhi BPB Publicaltions c1992. 1993 c1992. 1993 1992 Text xlii, 1002 p. : eng