APA

Davis P. H., Cullen J., . (1979). The identification of flowering plant families, including a key to those native and cultivated in north temperate regions. Cambridge: Cambridge University Press.

Chicago

Davis P H, Cullen J, . 1979. The identification of flowering plant families, including a key to those native and cultivated in north temperate regions. Cambridge: Cambridge University Press.

Harvard

Davis P. H., Cullen J., . (1979). The identification of flowering plant families, including a key to those native and cultivated in north temperate regions. Cambridge: Cambridge University Press.

MLA

Davis P H, Cullen J, . The identification of flowering plant families, including a key to those native and cultivated in north temperate regions. Cambridge: Cambridge University Press. 1979.