Another special claim form is a claim that includes a Markush group. Markush groups recite members as being “selected from the group consisting of A, B and C.”

Inventions in metallurgy, refractories, ceramics, pharmacy, pharmacology and biology are most frequently claimed under the Markush formula, but purely mechanical features or process steps may also be claimed by using the Markush style of claiming.

Incidentally, the terms “Markush” and “Jepson” take their names from the decisions that allowed the use of such claims.