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4. G.E.N. Scoon, J.-P. Lebreton, Venus sample return assessment study report, ESA Report SCI(98)3, June 1998, Noordwijk, The Netherlands.
5. A.D. McRonald, A light-weight inflatable hypersonic drag device for Venus entry, AAS Paper 99-355, presented at AIAA/AAS Astrodynamics Conference, Girdwood, Alaska, 19990816/19.