Gaya APA
Kirkpatrick, D, L., .Kirkpatrick, J, D. (2007).
implementing the four levels .
San Francisco:
Koehler Publicher.
Gaya MLA
Kirkpatrick, Donald, L.., .Kirkpatrick, James, D.
"implementing the four levels".
San Francisco:
Koehler Publicher,
2007.
Text.