Carney (1994)
h as a helper (auxiliary) letter in ch, sh and ph, p. 39; ch, p. 226; th, p. 232; sh, p. 240; wh, p. 253
(Under construction: the black bond bar, under letters that spell one consonant sound such as qu, wh and ng, is used from early in the route but isn't named as a new mark until step 25. Next: decide whether to name it at step 5.)