Ripman, W. The Sounds of Spoken English: A Manual of Ear Training for English Students (4th edition).
Chicago-viite (17. p.)Ripman, Walter. The Sounds of Spoken English: A Manual of Ear Training for English Students (4th Edition).
MLA-viite (9. p.)Ripman, Walter. The Sounds of Spoken English: A Manual of Ear Training for English Students (4th Edition).
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