What are the sources of the examples mentioned in Fatwa no. 36424 regarding hypothetical Fiqh?

May Allah, for whom you have shown love towards us, love you. It is inconceivable that the early scholars would have raised issues that were unimaginable in their era, such as artificial insemination. Rather, we have mentioned that some early scholars hypothesized issues that could occur in their time, and later scholars benefited from their solutions for other issues that arose in the modern era. As for organ transplantation, discussions about it are found in the books of the early scholars, such as the permissibility of mending bones with the bone of an animal whose meat is permissible to eat if it was slaughtered according to Islamic rites, and that it is absolutely impermissible to use a human bone. However, if no other bone is found except a human bone, it is permissible, and the bone of a disbeliever is to be preferred.