1. Castrén , J. A. Pohjola , S. Scleral rigidity at puberty To be publ. in Acta Ophth
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3. Contribution to the theory of tonometry.;Friedenwald;Am. J. Ophth.,1937
4. Tonometer calibration.;Friedenwald;Tr. Am. Acad. Ophth.,1957
5. Un nouveau tonométre àpplanation.;Goldmann;Bull. Soc. franc. Ophtal.,1955