private RefList getToRefs(Address to) {
		lock.acquire();
		try {
			long toAddr = addrMap.getKey(to, false);
			RefList refList = toCache.get(toAddr);
			if (refList == null) {
				try {
					refList = toAdapter.getRefList(program, toCache, to, toAddr);
				}
				catch (ClosedException e) {
					// TODO this seems wrong here; no other method handles closed exceptions
				}
				catch (IOException e) {
					dbError(e);
				}
			}
			return refList;
		}
		finally {
			lock.release();
		}
	}
Removes the external entry point at the given address
@param addr that address at which to remove the external entry point attribute.
Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/program/database/references/ReferenceDBManager.java