APA

Trusler I., Ehret W., . (1960). Functional lessons in singing. Englewood Cliffs: .

Chicago

Trusler I, Ehret W, . 1960. Functional lessons in singing. Englewood Cliffs: .

Harvard

Trusler I., Ehret W., . (1960). Functional lessons in singing. Englewood Cliffs: .

MLA

Trusler I, Ehret W, . Functional lessons in singing. Englewood Cliffs: . 1960.