(1990). Revised water usage & classification, water quality criteria amending section #68 & 69, chapter III of the NPCC rules and regulations. s.n.
Citazione stile Chigago Style (17a edizione)Revised Water Usage & Classification, Water Quality Criteria Amending Section #68 & 69, Chapter III of the NPCC Rules and Regulations. [s.l: s.n, 1990.
Citatione MLA (9a ed.)Revised Water Usage & Classification, Water Quality Criteria Amending Section #68 & 69, Chapter III of the NPCC Rules and Regulations. s.n, 1990.
Attenzione: Queste citazioni potrebbero non essere precise al 100%.