You may also wish to search for items by Shcherbakov, V. and Shcherbakov.
Only one matching reference was found.
Efremova, G.D.; Shcherbakov, V.I.; Pryanikova, R.O., Phase and volume ratios in the system hexamethylene diamine + ammonia, Khim. Prom-st. (Moscow), 1963, 39, 433-436. [all data]