If this basic grammatical unit is faulty, it may be marked "r/o" or "frag"
Halliday, 1989; 
Halliday,... [DOC] [TLE] A GRAMMAR OF THE HITTITE LANGUAGE Part 1 - lm 39 roma [PAR] A Grammar of the Hittite Language, by Harry A. Hoffner Jr. and H. Craig Melchert 
..... Parentheses within forms may mark optional modes of writing the word: e.g., -
az(a) ...... rarely if ever used by Hittitologists, we would advocate the use of the 
...... that within the historical period of Hittite there existed no more basic form from
... [DOC] [TLE] UCSC-CRL-90-19 [PAR] 2] A. W. Appel, \Garbage collection can be faster than stack allocation," 
Information.