APA
Wiefels P., . (2002). The Chasm Companion : A Fieldbook to Crossing the Chasm and Inside the Tornado. New York: Harper Business.
Chicago
Wiefels Paul, . 2002. The Chasm Companion : A Fieldbook to Crossing the Chasm and Inside the Tornado. New York: Harper Business.
Harvard
Wiefels P., . (2002). The Chasm Companion : A Fieldbook to Crossing the Chasm and Inside the Tornado. New York: Harper Business.
MLA
Wiefels Paul, . The Chasm Companion : A Fieldbook to Crossing the Chasm and Inside the Tornado. New York: Harper Business. 2002.