On 10 October 1902, The Baltimore Sun published in its Marriage Licenses column for Baltimore:
KOPP—RUMBEL.—William T. Kopp, 22, 17 North Durham street; Marguerite A. Rumbel, 18.
[The Baltimore Sun, 10 October 1902, page 7.]

On 15 May 1918, The Baltimore Sun published:
Several Granted Divorces
[Yesterday] Absolute divorces were granted to Margaret A. Kopp, 30 North Durham street, from William T. Kopp, with the custody of their two children…
[The Baltimore Sun, 15 May 1918, page 5.]

1920 U.S. Census, Baltimore City, Maryland
6th Ward, Enumeration District 64, Sheet 15B
17 Durham Street
Dwelling 216, Family 217
Kopp, Margaret, head, owns free of mortgage, female, white, 35, single, can read and write, born in Maryland, both parents born in Germany and spoke German, speaks English, no occupation
Kopp, Katherine, daughter, female, white, 16, single, not in school, can read and write, born in Maryland, both parents born in Maryland, speaks English, filer for telegraph company, wage worker
Kopp, Milton, son, male, white, 5, single, not in school, can read and write, born in Maryland, both parents born in Maryland, no occupation
Rumbel, George, father, male, white, 73, widowed, year of immigration 1870, naturalized in 1876, born in Germany, native language German, both parents born in Germany and spoke German, speaks English, watchman for packing house, wage worker
Rumbel, Frank, brother, male, white, 29, single, can read and write, born in Maryland, both parents born in Germany and spoke German, speaks English, driver of paint wagon, wage worker

1930 U.S. Census, Baltimore City, Maryland
6th Ward, Tract 10, Block 95, Enumeration District 4-70, Supervisor’s District 4, Sheet 1A
133 Bradford Street
Dwelling 3, Household 3
Cohen, Harry, head, owner, $2,000 in real estate, owns radio set, not on farm, male, white, age 27, married, not in school, can read and write, born in Russia, both parents born in Russia, native language Yiddish, immigrated in 1906, not naturalized, speaks English, occupation clerical worker for postal telegraph, wage worker, at work previous day
Cohen, Catherine, wife, female, white, age 24, married, not in school, can read and write, born in Maryland, both parents born in Maryland, no occupation
Cohen, Carroll R., son, male, white, age 3-6/12, single, not in school, born in Maryland, father born in Russia, mother born in Maryland, no occupation
Cohen, Irene M., daughter, female, white, age 6/12, single, not in school, born in Maryland, father born in Russia, mother born in Maryland, no occupation
Household 4
Kopp, Margaret, mother, female, white, age 45, unclear mark as to marital status, not in school, can read and write, born in Maryland, both parents born in Germany, speaks English, no occupation
Kopp, Milton C., brother, male, white, age 15, single, in school, can read and write, born in Maryland, both parents born in Maryland, speaks English, occupation messenger for postal telegraph, wage worker, at work previous day
Kopp, LeRoy E., brother, male, white, age 5, single, not in school, born in Maryland, both parents born in Maryland, no occupation

1940 U.S. Census, Baltimore City, Maryland
6th Ward, Enumeration District 4-100, Sheet 3B
133 Bradford Street, visited number 64, home owned, home value $1,250
Cohen, Katherine E., head, female, white, 36, married, not in school, highest grade attained 8, born in Maryland, living in same place in 1935, at private work, hours worked 40, telephone operator for postal telegraph, private work, weeks worked 52, income 769, has other income
Cohen, Carroll I., son, male, white, 14, single, in school, highest grade attained 5, born in Maryland, living in same place in 1935, not at work, no other income
Cohen, Irene M., daughter, female, white, 10, single, in school, highest grade attained 3, born in Maryland, living in same place in 1935
Kopp, Margaret, mother, female, white, 55, divorced, not in school, highest grade attained 4, born in Maryland, living in same place in 1935, engaged in housework, no other income
Kopp, Leroy, brother, male, white, 15, single, not in school, highest grade attained 4, born in Maryland, living in same place in 1935, not at work, no other income
Supplementary questions for Margaret Kopp: born parents born in Maryland, mother tongue is English, not a veteran, does not have a social security number, no occupation, not married more than once, age a first marriage 18, number of children ever born 3