Assalam o Alaikum,
I would like to share with you two very useful and important research papers (No. 5-a and No. 5-b), prepared by Engr. Muhammad Ali Mirza of Jehlum, Pakistan.
Download from his official website, http://ahlesunnatpak.com/research-papers/
1st research paper: No. 5-a
Analysis of Rawafidh, Nawasib and Yazidis from Quran and Sahih Ahadith.
2nd research paper: No. 5-b
Real background of Tragedy of Karbala from Sahih Ahadith.
JAZAK Allah KHAIRAN.
إِنَّ أَصْدَقَ الْحَدِيثِ كِتَابُ اللَّهِ وَأَحْسَنَ الْهَدْىِ هَدْىُ مُحَمَّدٍ وَشَرَّ الأُمُورِ مُحْدَثَات