context: Oberg continued to spend much of his time in the United States, teaching in university systems in both Missouri and Montana, and became a U.S. citizen in 1944.
source: Along with teaching in the United States, Oberg spent time both as a student and teacher in foreign countries.
reference_original: Junto con la enseñanza en los Estados Unidos, Oberg pasó tiempo como estudiante y profesor en países extranjeros.
reference_flipped: Junto con la enseñanza en los Estados Unidos, Oberg pasó tiempo como estudiante y profesora en países extranjeros.