Graue Haare Professor sitzt auf Tisch im Hörsaal und hält Buch - Stockfoto & -bild

Smiling grey hair professor standing in lecture room and looking at camera

Senior lecturer leaning on table and looking away

Smiling grey hair professor sitting on table in lecture room

Senior lecturer holding piece of chalk and looking away

Grey hair professor pointing on something at lecture hall

Smiling grey hair professor holding stack of books with apple on top

Smiling grey hair professor holding piece of chalk

Senior lecturer pointing on something in lecture room

Happy bearded speaker in glasses talking near microphones and brick wall

Handsome grey hair man sitting in armchair, holding old photos and looking away

Smiling senior man looking at camera while touching jacket isolated on grey

Elderly man in bow tie and blue jacket using smartphone isolated on grey

Positive senior man talking on smartphone and pointing with finger isolated on grey

Bearded speaker in glasses standing near microphones and brick wall

Smiling senior man in shirt and jacket pulling hand at camera on blurred foreground isolated on grey

Elderly man in shirt and jacket using smartphone isolated on grey