1. Arndt, H., Numerical Solution of Retarded Initial Value Problems: Local and Global Error and Stepsize Control, Numer. Math. 43 (1984), 343–360.
2. Bock H.G., Schlöder, J., Numerical Solution of Retarded Differential Equations with State-dependent Time Lags, Z. Angew. Math. Mech. 61 (1981), T269–271.
3. Driver, R.D., Existence Theory for a Delay-differential System, Contribution to Diff. Equations 1 (1963), 317–336.
4. El’sgol’ts, L.E. and Norkin, S.B., Introduction to the Theory and Application of Differential Equations with Deviating Arguments, Academic Press, New York — London (1973).
5. Hale, J., Theory of Functional Differential Equations, Springer, Berlin — Heidelberg — New York (1977).