Need Help With A Few Song ID's...

[Dave78]

Hey Purple fans! Like many here (I presume), I grew up in the 70's and
Deep Purple was one of the core groups I listened to, along with Led
Zep, Sabbath, The Nuge, Aerosmith and Van Halen. Good times!!

At any rate, fast forward 30 years or so and here I am trying to
remember a few things about three DP songs. They are:

1) Highway Star. I remember L.A. radio stations playing an alternate
studio version from time to time which began with about 10-15 seconds
of studio warm-up before the song actually began.

Also...

2) Smoke On The Water. As also heard on local L.A. radio, there was a
second live version of this fine song in which the opening riff
strayed a bit from the opening riff we are used to from both Machine
Head and Live In Japan.

Lastly...

3) Child In Time. I know this is on "In Rock" but iTunes does not
offer that particular cut so I am trying to track the studio version
down on a Best Of release which hopefully will also have one or both
of the two songs listed above.

So those are the three tracks I am trying to identify as to exactly
which CD they are on. If anyone can direct me as to which CD(s) I need
to buy for those versions, I would greatly appreciate it.

Thanks guys!