Many sources listed here:
http://en.wikipedia.org/wiki/Heisenberg_uncertainty
[This has a good discussion followed by a lot of references.]
Albert Messiah, Quantum Mechanics, p119
“When carrying out a measurement of position or momentum on an individual system represented by psi, no definite prediction can be made about the result. The predictions defined here apply to a very large number [N] of equivalent systems independent of each other each system being represented by the same wave function [psi]. If one carries out a position measurement on each one of them, The probability density P[r], or momentum density, gives the distribution of the [N] results of measurements in the limit where the number N of members of this statistical ensemble approaches infinity.”
:
http://arxiv.org/abs/1008.4591 ]
http://arxiv.org/abs/quant-ph/0609185
http://tf.nist.gov/general/pdf/1283.pdf
http://arxiv.org/abs/arXiv:1104.2822 Lee Smolin
A new ensemble interpretation of quantum mechanics is proposed according to which the ensemble associated to a quantum state really exists: it is the ensemble of all the systems in the same quantum state in the universe…The problem is that Smolin’s real ensemble is non-local.
ZapperZ explains this in his blog Misconception of the Heisenberg Uncertainty Principle.
the eigenstates corresponding to the respective measurement operators are incompatible. As a result, the system cannot simultaneously have both a definite value of qj and a definite value of pj. See Fourier Transforms and Uncertainty for more on this topic.
(mathpages:
http://www.mathpages.com/home/kmath523/kmath523.htm)
I'd also suggest you search these forums for discussions where you will find careful dissection about what HUPis and what it is NOT...