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236 pages first pub 1977 (editions)

nonfiction science informative reflective medium-paced
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560 pages first pub 1977 (editions)

nonfiction science informative reflective medium-paced

183 pages first pub 1977 (editions)

nonfiction science informative reflective medium-paced

268 pages first pub 1977 (editions)

nonfiction science informative reflective medium-paced