อ้างอิง ของ ปุ๋ย

  1. 1 2 3 4 ความรู้เรื่องปุ๋ย กรมส่งเสริมการเกษตร
  2. ↑ พระราชบัญญัติปุ๋ย คลังปัญญาไทย
  3. ↑ Controlled-Release Fertilizers by Warren Davenport; url=http://www.garden.org/subchannels/flowers/roses?q=show&id=698 (retrieved 22 June 2011)
  4. ↑ C. Neal, Slow-Release Fertilizers for Home Gardens and Landscapes, University of New Hampshire Cooperative Extension, url=http://extension.unh.edu/resources/representation/Resource000494_Rep516.pdf (retrieved 22 June 2011)
  5. ↑ T. M. Blessington, D. L. Clement, and K. G. Williams, SLOW RELEASE FERTILIZERS, Fact Sheet 870, Maryland Cooperative Extension, University of Maryland, College Park-Eastern Shore; url=http://extension.umd.edu/publications/pdfs/fs870.pdf (retrieved 22 June 2011)