context: As early as the late 1820s and early 1830s, she and her sister began opening infant schools in northeastern Ohio.
source: After obtaining a degree from Oberlin College in 1840s, Cowles began a formal career as a teacher.
reference_original: Cowles começou a trabalhar formalmente como professora depois de obter um diploma do Oberlin College em 1840.
reference_flipped: Cowles começou a trabalhar formalmente como professor depois de obter um diploma do Oberlin College em 1840.