Tchbanoglous, George
Solid wastes : engineering principles and mangement issues
McGraw-Hill, 1977
 Buku Teks SO
Helfert, Erich A.
Techniques of financial analysis
Richard D. Irwin, 1982
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Winston, Kwok Chee Chiu
Financial reporting and analysis
pearson Prentice Hall, 2007
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White, Gerald I.
The Analysis and use of financial statements
John Wiley & Sons, 1994
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Helfert, Erich A.
Techniques of financial analysis
Richard D. Irwin, 1977
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