Need help to get birth, marriage, death certificates in Warsaw, Poland between 1914-1919 #poland


My wife's grandparents married in Warsaw, Poland around 1914. My wife's mother was born in Warsaw in 1916. When my wife's mother was not 3 years old her parents got sick and the father past away.
My wife has no documents of her family in Warsaw. Anybody has tried to get marriage, birth and death certificates from Warsaw during the period 1914-1919? I appreciate your help.

Angel Kosfiszer

Richardson, Texas