@book{piotr+gamrat+w+swietle+nieznanego+zyciorysu,
    author = {Hartleb, Kazimierz},
    title = {Piotr Gamrat w świetle nieznanego życiorysu},
    address = {Lwów},
    publisher = {Towarzystwo Naukowe},
    date = {1938}
}