ϕsr+1(a0,a1,a2,,arb1,b2,,bs;q,z)=ϕsr+1(a0,a1,,ar;b1,b2,,bs;q,z)=n=0(a0;q)n(a1;q)n(ar;q)n(q;q)n(b1;q)n(bs;q)n((1)nq(n2))srzn.