Czyzak, S. J., & Aller, L. H. (1970). Spectrophotometric studies of gaseous nebulae XVII: Three planetaries with marked stratification effects: NGC 6309, NGC 7026 and IC 1747. University of California.
Chicago Style (17th ed.) CitationCzyzak, S. J., and Lawrence Hugh Aller. Spectrophotometric Studies of Gaseous Nebulae XVII: Three Planetaries with Marked Stratification Effects: NGC 6309, NGC 7026 and IC 1747. Los Angeles: University of California, 1970.
MLA (9th ed.) CitationCzyzak, S. J., and Lawrence Hugh Aller. Spectrophotometric Studies of Gaseous Nebulae XVII: Three Planetaries with Marked Stratification Effects: NGC 6309, NGC 7026 and IC 1747. University of California, 1970.
Warning: These citations may not always be 100% accurate.