O’Regan, Donal (1997). 《Existence Theory for Nonlinear Ordinary Differential Equations》. Mathematics and Its Applications (영어) 398. Dordrecht: Springer. doi:10.1007/978-94-017-1517-1. ISBN978-90-481-4835-6.
Cid, J. Ángel (2003년 5월 1일). “On uniqueness criteria for systems of ordinary differential equations”. 《Journal of Mathematical Analysis and Applications》 (영어) 281 (1): 264–275. doi:10.1016/S0022-247X(03)00096-9. ISSN0022-247X.
worldcat.org
Cid, J. Ángel (2003년 5월 1일). “On uniqueness criteria for systems of ordinary differential equations”. 《Journal of Mathematical Analysis and Applications》 (영어) 281 (1): 264–275. doi:10.1016/S0022-247X(03)00096-9. ISSN0022-247X.