1. F. Emich, Mikrochemisches Praktikum. Munich: J. F. Bergmann. 1931. p. 111.
2. A. A. Benedetti-Pichler, Theory and Practice of Sampling for Chemical Analysis, inW. G. Berl, Physical Methods of Chemical Analysis. New York: Academic Press. 1956.
3. S. Siggia, Private communication.
4. H. M. El-Badry, Micromanipulators and Micromanipulation. Mono-graphien aus dem Gebiete der qualitativen Mikroanalyse, Vol. III. Vienna: Springer-Verlag. 1963.
5. A. A. Benedetti-Pichler andM. Cefola, Ind. Eng. Chem., Analyt. Ed.14, 813 (1942).