Among older engineers and ham radio experimenters, the name Geffe is synonymous with "the blue filter book",   Simplified Filter Design, from 1963.

In 1999, he published a short article in RF Design magazine illustrating how to obtain an elliptic bandstop filter with reasonable part values.  This uses so-called "dipole transformations" that appear in Zverev's filter handbook.  Geffe's example shows how useful they can be.

The slides conclude with interesting biographical info for Philip R. Geffe.