Gaya APA
al.], R, A, D, .., Walker, . (1979).
Management of semi arid ecosystems .
Amsterdam:
Elsevier Science Publisher.
Gaya MLA
al.], Rolf, A., De, ...[et., Walker, .
"Management of semi arid ecosystems".
Amsterdam:
Elsevier Science Publisher,
1979.
Cetak.