[Ibn]

Hi everybody,
Please i really need your help,
I have created an epub with sigil and the book works great in my Ipad. Sigil validates the book (no errors) but when i submit it to the Applestore the validation process founds some errors in the book :

ERROR ITMS-9000: "OEBPS/Text/Section0001.xhtml(6): element "head" incomplete; missing required element "title". This error occurs 6 times." at Book (MZItmspBookPackage)
ERROR ITMS-9000: "OEBPS/Text/Section0003.xhtml(16): element "blockquote" incomplete; expected element "address", "blockquote", "del", "div", "dl", "h1", "h2", "h3", "h4", "h5", "h6", "hr", "ins", "noscript", "ns:svg", "ol", "p", "pre", "script", "table" or "ul" (with xmlns:ns="http://www.w3.org/2000/svg"). This error occurs 2 times." at Book (MZItmspBookPackage)

Itunesproducer (the apple tool to submit ebooks) proposes to repair the e-pub i submit but i don't know if it repairs it correctly. I prefer to do it myself.
Thank you very much for your help,
Ibn