Complex sentence: He received his doctor of science in 1948 (Kuno, 1950), he visited the United States in 1951-52 and worked with professor Harry H. Hess at Princeton University.
Split into simpler sentences: He received his doctor of science in 1948 (Kuno, 1950). He visited the United States in 1951-52 and worked with professor Harry H. Hess at Princeton University.