Gaya APA

Lemoff, T, C., Hammaker, F, G. (1988). National fuel gas code. (1988). : Arlington : AGA- NFPA,.

Gaya MLA

Lemoff, Theodore, C.., Hammaker, Forrest, G.. "National fuel gas code.". 1988 : Arlington : AGA- NFPA,, 1988. Text.