APA (7th ed.) Citation

V. N., R. (2012). Everything You Need to Know About XML Document Type Definitions (DTDs).

Chicago Style (17th ed.) Citation

V. N., Rao. Everything You Need to Know About XML Document Type Definitions (DTDs). 2012.

MLA (9th ed.) Citation

V. N., Rao. Everything You Need to Know About XML Document Type Definitions (DTDs). 2012.

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