ODF 1.2 part 3 public review comment: PNG not defined

Dear ODF committee,

Paragraph 2.8 "Preview Image" states
"Preview images shall be saved in PNG format."
but the PNG format is not defined. This should probably be something like 
ISO/IEC 15948:2003 Portable Network Graphics (PNG) Specification (Second 
Edition), http://www.w3.org/TR/2003/REC-PNG-20031110 .

Also, a typo in par. 7.2.1 "Conforming OpenDocument packages"
at (PD 1.4) "These file shall meet the requirements:"
should be "These files shall meet the requirements:"

Thanks!
Frits