American Psychological Association
Langen, Dietrich ( 1987 ). Speaking of Sleeping Problems Learning to Sleep Well Again ( 00 ed. ). Brbis Books.
Modern Language Association
Langen, Dietrich. Speaking of Sleeping Problems Learning to Sleep Well Again . Brbis Books. 1987
Chicago Citation
Langen, Dietrich. Speaking of Sleeping Problems Learning to Sleep Well Again . 00 .Maryknoll
: Brbis Books, 1987.
American Medical Association
Langen, Dietrich. Speaking of Sleeping Problems Learning to Sleep Well Again . Brbis Books; 1987.