Keeling was a Guggenheim fellow at the Meteorological Institute , University of Stockholm ( 1961–62 ) ; a guest professor at the Second Physical Institute of the University of Heidelberg ( 1969–70 ) and the Physical Institute of the University of Bern ( 1979–80 ) .
PROPN AUX DET PROPN NOUN ADP DET PROPN PROPN , PROPN ADP PROPN ( NUM ) ; DET NOUN NOUN ADP DET PROPN PROPN PROPN ADP DET PROPN ADP PROPN ( PROPN ) CCONJ DET PROPN PROPN ADP DET PROPN ADP PROPN ( PROPN ) .