Intro
In 1911, an Ahmadi, Muhammad Zahir Al-Din wrote a book wherein he discussed the prophethood of MGA and its implications of Kufr upon the Muslims of the world.  Mahmud Ahmad quotes this book in his 1924 book, “The truth about the split” and Muhammad Ali has quoted him quite a bit also in his books vs. Mahmud Ahmad.  Nonetheless, this book is totally missing from all records and archives in 2016.  The book may still exist in the Khilafat Library at Rabwah or Qadian, or even in the UK.

Yohanan Friedman direct quoted this book
Friedman’s book on Ahmadiyya was published in 1985, it was published again in 1989 and then 2003.  He seems to have had access to Zahir Al-Din’s book in 1985.

The Direct Quotes
1.  “His messengers (rusuluhu) is encountered in the Quran or in a declaration of faith, Ghulam Ahmad must be considered one of them.  Belief in him is a part of Islamic faith and is, as such, necessary for the attainment of salvation (madar-i najat)” (“Nabi-ullah Ka Zahoor” aka “Appearance of the Prophet of Allah” (1911) by Muhammad Zahir al-Din, see pages 8, 71 and 99)(From Friedman, page 152, 2003 edition).  

2.  “If the Promised Messiah is rejected or considered in his claim (heaven forbid!) a liar and a cheat—the inevitable result will be the loss of prophethood of Muhammad….as well”  (“Nabi-ullah Ka Zahoor”: aka “Appearance of the Prophet of Allah” (1911) by Muhammad Zahir al-Din, see page 80)(From Friedman, page 152, 2003 edition).