Import of honeybee prepromelittin into the endoplasmic reticulum: structural basis for independence of SRP and docking protein.
Muller G, Zimmermann R, EMBO J, 1987 Jul - link

Import of frog prepropeptide GLa into microsomes requires ATP but does not involve docking protein or ribosomes.
Schlenstedt G, Zimmermann R, EMBO J, 1987 Mar - link