APA
Keller P., . (1982). Getting at the core. England: Harvard University Press.
Chicago
Keller Phyllis, . 1982. Getting at the core. England: Harvard University Press.
Harvard
Keller P., . (1982). Getting at the core. England: Harvard University Press.
MLA
Keller Phyllis, . Getting at the core. England: Harvard University Press. 1982.