What is "entityRef" element in qbXML with TimeActivity - qbxml

Question

I am creating some time tracking software to interface with quickbooks, and below is my exported XML file. I receive status code 3140, saying there is an invalid reference to QuickBooks entity in the TimeTracking. Quickbooks returns error : "The secified record does not exist in the list."
I have observed that if I pull out the EntityRef tag from the XML file, Quickbooks throws a parsing error, but I am at a total loss as to what needs to be inserted within the EntityRef element.
<?xml version="1.0" encoding="UTF-8"?>
<?qbxml version="10.0"?>
-<QBXML>
-<QBXMLMsgsRq onError="stopOnError">
-<TimeTrackingAddRq>
-<TimeTrackingAdd>
-<EntityRef>
<FullName>Some List Name Here?</FullName>
</EntityRef>
<Duration>PT8h5M</Duration>
</TimeTrackingAdd>
</TimeTrackingAddRq>
</QBXMLMsgsRq>
</QBXML>

Answer 1

EntityRef/FullName can be either:
an employee FullName
a vendor FullName
or an "Other Name" list FullName
i.e. it's the person/company that you're tracking time for.
In other requests, it can also be a customer FullName. But in the case of Time Tracking, it doesn't make sense to track time for a customer.
Quoting from the QuickBooks OSR documentation:
Entity
A QuickBooks "entity" is a customer, vendor, employee, or
person on the QuickBooks "other names" list. Special cases to note:
In a BillToPayQuery message, EntityRef refers to the vendor name. In
JournalCreditLine and JournalDebitLine messages for A/R accounts,
EntityRef must refer to a customer, or else the transaction will not
be recorded. For A/P accounts the EntityRef must refer to a vendor, or
else the transaction will not be recorded. In a TimeTracking message,
EntityRef cannot refer to a customer, only to an employee, vendor, or
person on the "other names" list whose time is being tracked.