Which book of Proakis has dealt with continuous time signals and systems?
No, not as far as I know. I can recommend you two books dealing with continuous-time systems, the Fourier transform, and the Laplace transform, among other topics:


Signals and Systems, Oppenheim, Willsky: a classic, used copies can be found quite cheap
The Fourier Integral and Its Applications, Papoulis: less scary for an engineer than the title might make you think; it's actually much broader and very accessible; it deals with linear systems in general, low pass and band pass systems, the Laplace transform, etc.