Cite page of paper vs page of proceedings I am currently writing my thesis and I use several papers that are available als single PDFs like this one

I did not want to write the bibtex on my own, so I searched online and found this:

@inproceedings{Rozinat:2005:CTM:2179586.2179604,
 author = {Rozinat, A. and van der Aalst, W. M. P.},
 title = {Conformance Testing: Measuring the Fit and Appropriateness of Event Logs and Process Models},
 booktitle = {Proceedings of the Third International Conference on Business Process Management},
 series = {BPM'05},
 year = {2006},
 isbn = {3-540-32595-6, 978-3-540-32595-6},
 location = {Nancy, France},
 pages = {163--176},
 numpages = {14},
 url = {http://dx.doi.org/10.1007/11678564_15},
 doi = {10.1007/11678564_15},
 acmid = {2179604},
 publisher = {Springer-Verlag},
 address = {Berlin, Heidelberg},
} 


The problem: When citing a particular page of this paper, I use the page number of the single article PDF because I don't have access to the proceedings book as cited in my bibtex file. 

Is this a valid practice or should the page number equal the page number in the proceedings book?

If not, how would a correct bibtex look for this single PDF?
Page numbers are largely irrelevant. There are not so many dead tree copies around, and a digital copy may be modified. In that case, searching for the title on it is trivial. You are providing the DOI, that is a permanent identificator, so you don't have to worry about it.

On a practical thing, I just use DOI's API to get the citations, and leave them worry about the details:

[david@LCARS david]$ curl -LH "Accept: text/bibliography; style=bibtex" http://dx.doi.org/10.1007/11678564_15


That gives you:


  @article{Rozinat_2006, title={Conformance Testing: Measuring the Fit and Appropriateness of Event Logs and Process Models}, ISBN={http://id.crossref.org/isbn/978-3-540-32596-3}, ISSN={1611-3349}, url={http://dx.doi.org/10.1007/11678564_15}, DOI={10.1007/11678564_15}, journal={Lecture Notes in Computer Science}, publisher={Springer Science + Business Media}, author={Rozinat, A. and der Aalst, W. M. P.}, year={2006}, pages={163–176}}


It is easy, fast to generate if you have the DOI, and minimises the risk of typos.