(First-stage sampling units) can be establishments.Logical formLearned from2 sentences. Sampling can be at rates.Logical formLearned from2 sentences. (Hiv counseling) may use a methodology of respondent sampling.Logical formLearned from2 sentences. Readings may undergo a sampling.Logical formLearned from2 sentences. A sampling can be unrestricted.Logical formLearned from2 sentences. (Air sampling) may be undertaken.Logical formLearned from2 sentences. Methods can be for interpretting results of (air sampling).Logical formLearned from2 sentences. (Air sampling) can be appropriate.Logical formLearned from2 sentences. Disciplines may undergo a sampling.Logical formLearned from2 sentences. Some (drug injectors) may be recruited by (sampling techniques).Logical formLearned from2 sentences. Persons may present a sampling of presentation.Logical formLearned from2 sentences. An (urine sampling) can be observed.Logical formLearned from2 sentences. Abstinence may be monitored by analysis of (urine sampling).Logical formLearned from2 sentences. (Urine sampling) may undergo an analysis.Logical formLearned from2 sentences. Some (program participants) may be selected through sampling of some persons.Logical formLearned from2 sentences.