PPI. (1995). International soil fertility manual: To understand soil fertility is to understand a key to mankind`s survival on this planet. Potash and phosphate institute.
Chicago Edition CitationPPI. International Soil Fertility Manual: To Understand Soil Fertility Is to Understand a Key to Mankind`s Survival on This Planet. United States: Potash and phosphate institute, 1995.
MLA Edition CitationPPI. International Soil Fertility Manual: To Understand Soil Fertility Is to Understand a Key to Mankind`s Survival on This Planet. Potash and phosphate institute, 1995.
Warning: These citations may not always be 100% accurate.