Sheffield, L., & Sheffield, N. Swimming simplified revised and enlarged edition / by Lyba and Nita Sheffield, A. M. directors of swimming at the Universities of California and Columbia (summer sessions), and (nita sheffield) instructor of physical education, tachers college.
Cita Chicago Style (17a ed.)Sheffield, Lyba, y Nitta Sheffield. Swimming Simplified Revised and Enlarged Edition / by Lyba and Nita Sheffield, A. M. Directors of Swimming at the Universities of California and Columbia (summer Sessions), and (nita Sheffield) Instructor of Physical Education, Tachers College. New York : A. S. Barnes and company, 1929.
Cita MLA (8a ed.)Sheffield, Lyba, y Nitta Sheffield. Swimming Simplified Revised and Enlarged Edition / by Lyba and Nita Sheffield, A. M. Directors of Swimming at the Universities of California and Columbia (summer Sessions), and (nita Sheffield) Instructor of Physical Education, Tachers College.