Gaya APA

(API), A, P, I. (1987). Specification for polythylene line pipe (PE) API Specification 15LE (Spec 15LE) (1987). : Washington DC : American Petroleum Inst.,.

Gaya MLA

(API), American, Petrol., Inst.. "Specification for polythylene line pipe (PE) API Specification 15LE (Spec 15LE)". 1987 : Washington DC : American Petroleum Inst.,, 1987. Text.