Kirill Sidorov

Countries of the world

Wood species

Fighter aircraft World War II

Structural geology

Fruit trees

The rulers of Italy

Trees

Disappeared European states

Programming languages

Algorithms

Mathematical logic

Perennial herbs

Military aircraft

Units of measure

Chess Tactics

Fruit

Graph theory

Natural phenomena

Fabrics

Owls

Electromagnetism

Economic terms

Physical laws

Breeds of horses