at the same time, milanković wrote four sections of beno gutenberg's "handbook of geophysics" (handbuch der geophysik) – "the earth's position and movement in space", "rotational movement of the earth", "secular shift of the poles", and "astronomic means for climate study during the earth's history" – published by wegener's father-in-law köppen in 1933. the lecture on the apparent shift of poles was held at a congress of balkan mathematicians in athens in 1934. that same year, milanković published an article dedicated to the work alfred wegener under titled "moving of the earth's poles – a memory to alfred wegener".