@bookHahn_2023, title=Learning the pronunciation of segmental features of english phonology at german primary schools, DOI=10.17619/UNIPB/1-1802, publisher=LibreCat University, author=Hahn, Charlotte Anna, year=2023 

@bookFreudinger_2013, place=Paderborn, title=Syntactic perspectives on directive speech actsf: a contrastive study, publisher=Universitätsbibliothek Paderborn, author=Freudinger, Markus, year=2013