Can someone help me with 2 document/source based essays?

i'm taking AS history and the other day we got given two document/source based questions. We have to use both the documents given and our own knowledge as i guess you already know. We're told to consider the authorship of the extracts and reasons for writing them but i don't really know much about them...
it's for monday and i was wondering if i could get some help cause i'd reallllllly apprecite it!

thanks
the first question is 'To what extent was Germany responsible for the outbreak of war in August 1914'
and the other is 'did the schlieffen plan fail due to German miscalculation or allied strength?'

the Germany question includes a extract from the December war council meeting, a diary entry from K.Riezler, secretary to Bethmann Hollweg, and an extract from F.R Bridge's 1914: the coming of the first world war.

the schlieffen plan question contains an extract from Farrar LL. the stratergy of the centralm powers, 1914-17 in 1998, an extract from the first world war by Keegan, J, an extract from Tucker SC, the great war and two British infantry officers commenting on the conditions of warfare on the western front.

i'm fine with the Germany question but i don't really know what to say about the Authors, the Schlieffen plan question i'm completely stuck on. i have to hand it in tomorrow so i'd love some help!

however, you can almost garentee that they wont be biased.