Sapphires Heated with Pressure – A Research Update. Published in InColor, Spring 2019, 86-90.
Trapiche-Rubine. Published in GZ, 1997.
Author(s): K. Schmetzer, H.A. Haenni, H.-J. Bernhardt, D. Schwarz
The emeralds of Fazenda Boa Esperanca, Taua, Ceara, Brazil: occurence and properties. Published in Journal of Gemmology, 1988.
Author(s): D. Schwarz, H.A. Haenni, F.L. Martins Jr, M. Fischer
Die Smaragde der Fazenda Boa Esperenca bei Taua, Ceara, Brasilien: Vorkommen und Charateristika. Published in Zeitschrift der Deutschen Gemmologischen Gesellschaft, 1988.
Author(s): D. Schwarz, H.A. Haenni, F.L. Martins Jr, M. Fischer
The emeralds from the Belmont Mine, Minas Gerais, Brazil. Published in Journal of Gemmology, 1987.
Author(s): H.A. Haenni, D. Schwarz, M. Fischer
Die Smaragde der Belmont-Mine bei Itabira, Minas Gerais, Brasilien: Vorkommen und Charakteristika. Published in Zeitschrift der Deutschen Gemmologischen Gesellschaft, 1987.
Author(s): H.A. Haenni, D. Schwarz, M. Fischer