Can somebody help me finding the documentation where the significance, functional importance & the advantages of the additional circuits like the pull-ups, bypass capacitors etc. are explained.

I gave you excellent links about the bypassing and filtering issue. Did you already read them???

Like I said the pull-ups will help me maintaining the data level stable for long wired devices.

Mmh, confuses me bit.
First of all, a pull-up is needed if output of gate is not made in push-pull technology. Means, when you use chips with open-collector or open-drain outputs, like 74LS05 or 74HC09. Then, this pull-up is real essential, because otherwise you will never be able to fabricate logic high state.
Today, it's not wise to use open-collector or open-drain circuits, unless you are forced to use Port0 of '51 derivative in typical port mode (when output looks like open-drain topology).

One big disadvantage of open-collector or open-drain technology is, that in order to achieve fast rise times pull-ups must be decreased to idiotic small levels. LSTTL for instance specifies many dynamic data (propagation delay times, etc.) with pull-ups of 110Ohm. So, whenever output transistor turns-on 45mA current is flowing from Vcc to ground. This is more then a whole 89C52 board!!

So, whenever capactive load is high and fast rise times must be provided, pull-ups must be decreased to rather impractical levels.

What you meant with the 'long wired devices', I can only guess. If you have long signal lines in a digital circuit, you must think in terms of transmission line technique. Means, your signal line now has a characteristic impedance, which needs impedance matched drivers and recievers at both ends. Otherwise your signal integrity will suffer from ringing, reflections and other stuff. This issue is also discussed in the links I gave you: Transmission line technique, impedance matching and signal filtering as well. Everything explained in total detail. You must only read it...

Finally, there's one application, where some people add pull-ups with standard '51 derivatives: /RD and /WR signals are fabricated by push-pull output. Means, for two oscillator periods very low ohmic output transistors forces the line to toggle from low to high or vice versa. But then, some periods later, if the line is deactivated again (makes high level), strong internal active pull-up is switched-off and only weak internal active pull-up is present. Then, output impedance rises to several dozens of kiloOhms. This CAN make the circuit more sensitive to digital noise, because charge injecting through stray capacitance has a better chance to penetrate due to higher impedance. Then, it CAN be helpful, when 4.7k...10k pull-ups are connected to /RD and /WR lines. This is the case for instance, if these lines are rather long. But the adding of these pull-ups is more cosmetics then a real demand...

Kai