for whom did she report?
"The Atlanta Journal Sunday Magazine"
Margaret Mitchell
While still legally married to Upshaw and needing income for herself, Mitchell got a job writing feature articles for "The Atlanta Journal Sunday Magazine". 
where does the movie gone with the wind take place California, mostly in Los Angeles County or neighboring Ventura County is it a novel adaptation? Yes, adapted from the novel by Margaret Mitchell mention a few of her other works? "Gone with the Wind" and "Lost Laysen" is "the big four" also her work? Yes,  a 400-page novel about girls was she a reporter too? Yes, she was a journalist
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Margaret Mitchell [SEP] Reporter for "The Atlanta Journal"
While still legally married to Upshaw and needing income for herself, Mitchell got a job writing feature articles for "The Atlanta Journal Sunday Magazine". She received almost no encouragement from her family or "society" to pursue a career in journalism, and had no prior newspaper experience. Medora Field Perkerson, who hired Mitchell said: There had been some skepticism on the Atlanta Journal Magazine staff when Peggy came to work as a reporter. Debutantes slept late in those days and didn't go in for jobs. Her first story, "Atlanta Girl Sees Italian Revolution", by Margaret Mitchell Upshaw, appeared on December 31, 1922.