ファイナンスへの応用を前提にした"易しい"入門書としては,
[1] Shreve, Steven E. Stochastic calculus for finance. II.
Continuous-time models. Springer Finance. Springer-Verlag, New York, 2004.
"キチンと"書いてあって頑張れば読めるものとしては,
[2] Protter, Philip E. Stochastic integration and differential equations.
Second edition. Version 2.1. Corrected third printing.
Stochastic Modelling and Applied Probability, 21. Springer-Verlag, Berlin, 2005.
[3] Chung, K. L.; Williams, R. J. Introduction to stochastic integration.
Second edition. Modern Birkhäuser Classics. Birkhäuser/Springer, New York, 2014.
[4] Cohen, Samuel N.; Elliott, Robert J.Stochastic calculus and applications.
Second edition. Probability and its Applications. Springer, Cham, 2015.
[5] Karatzas, Ioannis; Shreve, Steven E. Brownian motion and stochastic calculus.
Second edition. Graduate Texts in Mathematics, 113. Springer-Verlag, New York, 1991.
など. その他講義中に紹介する.