9-305:when possession by secured party perfects security interest without filing
9-306:proceeds; secured party's rights on disposition of collateral
9-307:protection of buyers of goods
-9-310:periority of certain liens arising by opration of law (mechanic's liens)
+9-310:periority of certain liens arising by operation of law (mechanic's liens)
9-311:alienability of debtor's rights; judicial process
9-312:priorities among conflicting security interests in the same collateral
9-405:assignment of security interest