issue with Thurber's system is the manner of letter formation. The addition of so-called "monkey tails" to print writing as learners progress to cursive writing effectively adds a further step to the teaching and learning path. While some find such an additional step beneficial for a smooth transition from print writing to cursive, others view it as unnecessarily complicating how children are taught to write. Another common issue is that D'Nealian is taught extremely early, to first and second grade students, many of whom are still learning the rudiments of print writing. At times, some school districts have abruptly changed their teaching of handwriting, possibly causing difficulties for students who must then adapt to a different style. A 1993 research review by Steve Graham concludes that "there is no credible evidence" that D'Nealian makes a difference in children's handwriting. He also states that D'Nealian creates practical problems for teachers (who must themselves learn the system and defend it to parents) and that it requires many young children to unlearn writing forms that they have already developed before formal instruction. See also Spencerian script, a US teaching script Palmer script, a US teaching script Zaner-Bloser script, a US teaching script Getty-Dubay Italic script, a US teaching script BFH script, a US teaching script Regional handwriting variation References Penmanship Typefaces and fonts introduced in 1978 Western calligraphy