(1990). Revised water usage & classification, water quality criteria amending section #68 & 69, chapter III of the NPCC rules and regulations. s.n.
Cita Chicago (17th ed.)Revised Water Usage & Classification, Water Quality Criteria Amending Section #68 & 69, Chapter III of the NPCC Rules and Regulations. [s.l: s.n, 1990.
Cita MLA (9th ed.)Revised Water Usage & Classification, Water Quality Criteria Amending Section #68 & 69, Chapter III of the NPCC Rules and Regulations. s.n, 1990.
Atenció: Aquestes cites poden no estar 100% correctes.