This is what I have so far...

Create Table Author(Aid integer primary key, First text, Last text)

Create Table Writes(Booknum integer references Book(Booknum), Aid integer references Author(Aid), Percent integer, primary key Booknum(Aid)

Create Table Book(...haven't done this one yet)

Create Table Copy(Copynum integer primary key, Price decimal(8,2), Booknum not null, foreign key(Booknum) references Book(Booknum))

Create Table Loan(Loannum integer primary key, Out text, Due text, Ret text, foreign key(Copynum) references Copy(Copynum))

Create Table Customer(...haven't done this one yet)