My personal experience I stated is solid proof that bench pressing will help you increase pushups without ever even doing one. You don't need a scientific study for everything. Increasing pressing strength helps no matter how you look at it, whether it's with weighted pushups or a bench press it is essentially the same motion. No scientific study that could be performed would contradict that statement and I'm willing to bet 500,000 karma on that, and a splintered and spiked wooden log rammed up my ass.
If you took a 2 subjects that both had a 25 rep maximum and one did bench pressing, and the other did nothing for 8 weeks, the subject that did bench pressing is most definitely, undoubtedly, with 100% assurance going to increase the amount of reps on his push ups (most likely atleast doubling it) while the other kids would remain virtually the same. You think that's wrong? Then I'd kill myself if I was that stupid.