APA (7th ed.) Citation

Corp, I. IBM Disk Operating System version 4.00: Getting started using disk. IBM Corporation.

Chicago Style (17th ed.) Citation

Corp, IBM. IBM Disk Operating System Version 4.00: Getting Started Using Disk. IBM Corporation.

MLA (8th ed.) Citation

Corp, IBM. IBM Disk Operating System Version 4.00: Getting Started Using Disk. IBM Corporation.

Warning: These citations may not always be 100% accurate.