Abler , R., & Alber, R. .. ,. (1975). Human geography in a shrinking world: By Ronald Abler , Donald Janelle , Allen Philbrick and John Sommer. Duxbury.
Cita Chicago (17th ed.)Abler , Ronald, i Ronald . ,,, Alber. Human Geography in a Shrinking World: By Ronald Abler , Donald Janelle , Allen Philbrick and John Sommer. Massachusetts: Duxbury, 1975.
Cita MLA (9th ed.)Abler , Ronald, i Ronald . ,,, Alber. Human Geography in a Shrinking World: By Ronald Abler , Donald Janelle , Allen Philbrick and John Sommer. Duxbury, 1975.
Atenció: Aquestes cites poden no estar 100% correctes.