void removeReference(Address fromAddr, Address toAddr, int opIndex) {
		lock.acquire();
		try {
			Reference ref = null;
			RefList fromRefs = getFromRefs(fromAddr);
			if (fromRefs != null) {
				ref = fromRefs.getRef(toAddr, opIndex);
				if (ref != null) {
					fromRefs.removeRef(toAddr, opIndex);
					if (fromRefs.isEmpty()) {
						fromCache.delete(fromRefs.getKey());
					}
				}
			}
			RefList toRefs = getToRefs(toAddr);
			if (toRefs != null) {
				if (ref == null) {
					ref = toRefs.getRef(fromAddr, opIndex);
				}
				toRefs.removeRef(fromAddr, opIndex);
				if (toRefs.isEmpty()) {
					toCache.delete(toRefs.getKey());
				}
			}
			if (ref != null) {
				referenceRemoved(ref);
			}
		}
		catch (IOException e) {
			dbError(e);
		}
		finally {
			lock.release();
		}
	}
Get all memory references with the given from address at opIndex.
@param fromAddr the from address
@param opIndex the operand index
@return the references
Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/program/database/references/ReferenceDBManager.java