1. “Manson's Tropical Diseases” Tenth Edition page200.
2. M.Nagayo T.Tamiya T.MitamuraandK.Sato: “On the Virus of Tsutsugamushi Disease and its Demonstration by a New Method” Japanese Journal of Experimental Medicine August 20 1930 page309(quoted in the Annual Report of the Institute for Medical Research Federated Malay States 1931 page 33).
3. R.Lewthwaite: “Clinical and Epidemiological Observations on Tropical Typhus in the Federated Malay States” “Bulletin from the Institute for Medical Research” Federated Malay States Number 1 of1930.
4. Die fleckfieberartigen Krankheitendes südlichen Afrika;Pijper A.;Zentralblatt für Bakteriologie, Parasitenkunde und Infektionskrankheiten,1934