Welch, W. W. (1971). A summary of research in science education for the years of 1968-69 secondary school level. ERIC.
Chicago-čujuhus (17. p.)Welch, Wayne W. A Summary of Research in Science Education for the Years of 1968-69 Secondary School Level. Ohio, Estados Unidos: ERIC, 1971.
MLA-čujuhus (9. p.)Welch, Wayne W. A Summary of Research in Science Education for the Years of 1968-69 Secondary School Level. ERIC, 1971.
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