“…Kambe & Miyake, 1954;Hart & Lang, 1961;Colella, 1974;Post, 1977;Chapman, Yoder & Colella, 1981;H~ier & Aanestad, 1981;Chang, 1982;Juretschke, 1982;Hiimmer & Billy, 1986;Shen & Colella, 1988;Mo, Haubach & Thorkildsen, 1988;Chang & Tang, 1988;Hiimmer, Weckert & Bondza, 1989). In the case of grazing-incidence X-ray diffraction, abbreviated as GIXD (Marra, Eisenberger & Cho, 1979;Vineyard, 1982;Afanas'ev & Melkonyan, 1983;Cowan, 1985;Hoche, Briimmer & Nieber, 1986;Sakata & Hashizume, 1988;Fuoss, Liang & Eisenberger, 1989;Durbin & Gog, 1989;Hung & Chang, 1989), X-ray reflection phases should, in principle, also be involved in multi-beam diffraction processes. However, reports on this particular phase problem have not been found in the literature.…”