Daniel:
The best analysis and definition of International Management can be found in: John Fayerweather (1969), International Business Management: A Conceptual Framework (New York: McGraw-Hill). It is its oldest but still most relevant definition in economic, social, political and integrational terms.
It should not be difficult to substitute "strategy" for "management" in Fayerweather's definition because there are many definitions of the former.
For further analyses, see Jean J. Boddewyn (1999). "The Domain of International Management," Journal of International Management , 5, pp. 3-14.
Jean J. Boddewyn, Brian Toyne and Z.L. Martinez (2004). "The Meanings of 'International Management'," Management International Review , 44(2), pp.195-212.
Jean J. Boddewyn and G. Iyer (1999), "International-Business Research: Beyond Deja Vu," Management International Review , Special Issue, (2), pp. 161-184.
Good luck and let me see what definition you ended up with!
Jean Boddewyn