Although this was the official position, in fact Seifert returned to Dresden every weekend and he worked with Threlfall, so certainly Threlfall was an unofficial supervisor.
Kahit na ito ay ang opisyal na posisyon, sa katunayan Seifert ibabalik sa Dresden bawat linggo at siya ay nagtrabaho sa Threlfall, kaya tiyak Threlfall ay hindi isang tagapamahala.