I'd prefer myself to start from an introductory book or a lecture before diving into research papers.

The most often recommended book on the rietveld_l mailing list (which is the biggest mailing list about powder diffraction) is:

Fundamentals of Powder Diffraction and Structural Characterization of Materials by Vitalij K. Pecharsky & Peter Y. Zavalij.

Note that rietveld_l is a low-traffic list and most-often recommended there means a few times per decade.

I'd prefer myself to start from an introductory book or a lecture before diving into research papers.

The most often recommended book on the rietveld_l mailing list (which is the biggest mailing list about powder diffraction) is:

Fundamentals of Powder Diffraction and Structural Characterization of Materials by Vitalij K. Pecharsky & Peter Y. Zavalij.

Note that rietveld_l is a low-traffic list and most-often recommended there means a few times per decade.