3993862 GMFCS Gross Motor Function Classification System 1636 3873554 GFMCS Gross Motor Function Classification System 3 2431560 GMFCS-ER Gross Motor Function Classification System 3 3994070 GMFSC gross motor function classification system 2 3993201 GMCFS Gross Motor Function Classification System 1 2788041 GMCS Gross Motor Function Classification System 1 3688167 GMFCS I-II Gross Motor Function Classification System 1