Reception In several MISC@1 states , articles from the books have been used officially as teaching materials , and -- according to Sick 's foreword of August NUMBER@1 -- the series has been added to the set text list for the Abitur in LOCATION@1 .

In several states of LOCATION@2 , writings from the books have been officially recognized as teaching documents after Sick 's foreword was used in LOCATION@1 in August NUMBER@1 .
