VCO555 question

[--M]

    First let me thank you all for the op amp theory very enlightening.
I found the Schematic and PCB layout for a VCO based around the 555.

http://www.xavax.com/efm/synth/cbook/pics/vco555a_sd.gif

    There are three transistors in this circuit, what part number are
these or does it matter as long as I get the correct type of transistor?

Thanks

--M

PS I would like to thank TomG for his web site which is one of if not
the best synth-Diy resource on the internet. If any of you have not
checked it out you should go take a look.