Published in Scopus, in 1990, in volume 14, pages 1-5

Published in Scopus, in 1990, in volume 14, pages 6-13

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Published in Scopus, in 1990, in volume 14, pages 19-20

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Published in Scopus, in 1990, in volume 14, pages 21-22

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Published in Scopus, in 1990, in volume 14, pages 30

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Published in Scopus, in 1990, in volume 14, pages 33

Published in Scopus, in 1990, in volume 14, pages 34-35