Graue Haare Professor hält Stapel von Büchern mit Apfel auf dem Kopf - Stockfoto & -bild

Thoughtful senior lecturer sitting at table with pencil and notebook

Smiling grey hair professor holding wooden pointer

Grey hair professor showing fist to students

Smiling grey hair professor holding paper plane in lecture hall

Grey hair professor using laptop at table in lecture hall

Senior lecturer holding book and pointing on something

Rear view of senior lecturer writing something on blackboard with piece of chalk

Thoughtful senior man with pencil and sheet of paper

Senior man in tweed suit reading notes in notebook with magnifying glass

Smiling elderly man looking at camera while holding laptop isolated on grey

Cheerful businessman in glasses voting near brick wall

Pensive handsome grey hair man thinking and looking at chessboard at home

Serious senior man writing in notebook with pencil

Pensive handsome grey hair man holding book and looking at camera

Handsome grey hair man reading book at home

Senior writer in tweed suit and eyeglasses with letter near workplace

Serious senior businessman adjusting eyeglasses while looking at camera isolated on black