Beltran, D. G. (1973). A method of determining economical sample size for sample surveys [microform]. Photoduplication Service.
शिकागो शैली (17वां संस्करण) प्रशस्ति पत्रBeltran, Disodado G. A Method of Determining Economical Sample Size for Sample Surveys [microform]. Quezon City: Photoduplication Service, 1973.
एमएलए (9वां संस्करण) प्रशस्ति पत्रBeltran, Disodado G. A Method of Determining Economical Sample Size for Sample Surveys [microform]. Photoduplication Service, 1973.
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