17. Documents of which registration is compulsory
17A. Registration of contract for sale, etc.
17B. Effect of unregistered contract for sale executed prior to section 17A becomes effective
18. Documents of which registration is optional
19. Documents in language not understood by registering officer
20. Documents containing interlineations, blanks erasures or alterations
21. Description of property and maps or plans
22. Description of houses and land by reference to Government maps or surveys