Gaya APA
People and Progress. (1947).
USA:
Scott, Foresman and Company.
Gaya Chicago
People and Progress.
.
USA:
Scott, Foresman and Company,
1947.
.
Gaya MLA
People and Progress.
.
USA:
Scott, Foresman and Company,
1947.
.
Gaya Turabian
People and Progress.
USA:
Scott, Foresman and Company,
1947.
.