Tōkyō Kōken K.K. (東京光研㈱, meaning Tokyo Optical Research) was a Japanese company which made the Dolca 35 cameras from late 1952 to early 1956. Its address was Arakawa-ku Nippori (荒川区日暮里) 8–577 in Tokyo.
- Advertisements dated September 1954 to February 1956 reproduced in Kokusan kamera no rekishi, pp. 154 and 260.
- Asahi Camera (アサヒカメラ) editorial staff. Shōwa 10–40nen kōkoku ni miru kokusan kamera no rekishi (昭和10–40年広告にみる国産カメラの歴史, Japanese camera history as seen in advertisements, 1935–1965). Tokyo: Asahi Shinbunsha, 1994. ISBN 4-02-330312-7.