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- Hengst, S. (author), Stijnen, P. (author), Spaarman, R. (author) other 1988
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- Hengst, S. (author), Stijnen, P. (author) other 1987
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- Hengst, S. (author), Koele, J.W. (author), Stijnen, P. (author) other 1987
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- Hengst, S. (author), Stijnen, P. (author) other 1987
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- Hengst, S. (author), Koele, J.W. (author), Stijnen, P. (author) other 1987
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- Hengst, S. (author), Stijnen, P. (author) other 1986
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- Hengst, S. (author), Stijnen, P. (author) other 1986