APA (7th ed.) Citation

Puglisi, S., Simpson, J., & Smyth, W. (2008). How many runs can a string contain? Elsevier.

Chicago Style (17th ed.) Citation

Puglisi, S., Jamie Simpson, and William Smyth. How Many Runs Can a String Contain? Elsevier, 2008.

MLA (9th ed.) Citation

Puglisi, S., et al. How Many Runs Can a String Contain? Elsevier, 2008.