Gaya APA

Williams, George A., Barnes, Richard A.. (1979). Challenges to science physical science (teachers edition) . United States of America: McGraw-Hill, Inc.

Gaya Chicago

Williams, George A., Barnes, Richard A.. Challenges to science physical science (teachers edition). United States of America: McGraw-Hill, Inc, 1979. Text.

Gaya MLA

Williams, George A., Barnes, Richard A.. Challenges to science physical science (teachers edition). United States of America: McGraw-Hill, Inc, 1979. Text.

Gaya Turabian

Williams, George A., Barnes, Richard A.. Challenges to science physical science (teachers edition). United States of America: McGraw-Hill, Inc, 1979. Print.