Παραπομπή APA

Roy, A. E., & Clarke, D. (1977). Astronomy: Principles and practice. Adam Hilger.

Παραπομπή Chicago Style

Roy, A E., και D. Clarke. Astronomy: Principles and Practice. Bristol: Adam Hilger, 1977.

Παραπομπή MLA

Roy, A E., και D. Clarke. Astronomy: Principles and Practice. Adam Hilger, 1977.