While it may be fair to say the number isn't "hundreds" (or maybe it is?) I will say that I'd take that Google Scholar number with a grain of salt. Just poking around looking for stuff in the spirit of this sub-thread, I've found 4 or 5 additional documents that cite the SHARD paper, and which aren't on that Google Scholar list.
I've found that Google Scholar's coverage gets a little sketchy on older stuff, and since we're talking way back in the 1980's here, I don't think it's surprising that some things are missing.
I've found that Google Scholar's coverage gets a little sketchy on older stuff, and since we're talking way back in the 1980's here, I don't think it's surprising that some things are missing.