[1] B. Gerlach: 
A characterization of availability with statistical applications. Math. Operationsforsch. u. Statist., Ser. Statistics 9(1978), 4, 563 - 586. 
MR 0531995 | 
Zbl 0408.62083[2] B. Gerlach W. Warmuth: 
Some remarks to system availability. Math. Operationsforsch. u. Statist. 7 (1976), 4, 601-606. 
MR 0423731[3] H. L. Gray T. O. Lewis: 
A confidence interval for availability ratio. Technometrics 9 (1967), 465-471. 
MR 0216705[4] H. L. Gray W. R. Schucamy: Lower confidence limits for availability assuming log-normally distributed repair times. IEEE Trans. Rel. 18 (1969), 157- 162.
[5] S. Karlin A. Novikoff: 
Generalized convex inequalities. Pacific J. Math. 13 (1963), 1251-1279. 
MR 0156927[6] H. F. Martz: On single-cycle availability. IEEE Trans. Rel. 20 (1971), 21-23.
[7] D. Stoyan: 
Qualitative Eigenschaften und Abschätzungen stochastischer Modelle. Akademie-Verlag, Berlin 1977. 
MR 0455157 | 
Zbl 0395.60082[8] M. Thompson: Lower confidence limits and a test of hypotheses for system availability. IEEE Trans. Rel. 15 (1966), 32-36.