What is Otoscope, its History and who is its Inventor?

Guys, can you help me with my research? I have research regarding Otoscope its history, design and inventor. So far I only have one reliable resource.

Here is some excerpt:

"As early as 1363, Guy de Chauliac of France illustrated the very first design of otoscope which comes in a tong shape specula and has the capacity to examine the aural and nasal passages. Ancient ear specialists make use of this medical instrument for almost half a century. In 1838, Ignaz Gruber of Italy tried to redesign the said device to a funnel shape specula but unfortunately, his invention remains unpublished. Then in 1864, E.Siegel from Germany introduced a new model of medical instrument for ear check up called pneumatic otoscope."

That is from http://www.ubscure.com/Art/166638/49/An-Overview-of-Otoscope-Designs.html

Do you have any resource?

thanks. badly needed for my research subject. thanks!