Graduate student Nina Feygl Semushina and faculty member Rachel Mayberry published a paper Numeral Incorporation in Russian Sign Language: Phonological Constraints on Simultaneous Morphology in Sign Language Studies, vol. 20 no. 1.
Abstract. Numeral incorporation is the simultaneous combination of a numeral and a base sign into one sign. Incorporating forms typically use the numerical handshape combined simultaneously with the movement, location, and orientation of the base lexical sign: for example, “3 months” will be expressed through an incorporating form 3_MONTH. Analyses of Russian Sign Language (RSL) data collected through fieldwork in Russia, show that there is no general linguistic rule for numeral incorporation in RSL (unlike in ASL which has a one-handed numeral system). Instead, because of phonological constraints that govern the distribution of two-handed signs, incorporation of two-handed numerals in RSL depends upon the place of articulation and the hand orientation of the particular lexical sign.