| Letter | Subject |
| Class A | |
| AC | |
| AE | |
| AG | |
| AI | |
| AM | |
| AN | |
| AP | |
| AS | |
| AY | |
| AZ | |
| Class B | |
| B | |
| BC | |
| BD | |
| BF | |
| BH | |
| BJ | |
| BL | |
| BM | |
| BP | |
| BQ | |
| BR | |
| BS | |
| BT | |
| BV | |
| BX | |
| Class C | |
| C | |
| CB | |
| CC | |
| CD | |
| CE | |
| CJ | |
| CN | |
| CR | |
| CS | |
| CT | |
| Class D | |
| D | |
| DA | |
| DAW | |
| DB | |
| DC | |
| DD | |
| DE | |
| DF | |
| DG | |
| DH | |
| DJ | |
| DJK | |
| DK | |
| DL | |
| DP | |
| DQ | |
| DR | |
| DS | |
| DT | |
| DU | |
| DX | |
| Class E | |
| | Letter | Subject |
| Class F | |
| Class G | |
| G | |
| GA | |
| GB | |
| GC | |
| GE | |
| GF | |
| GN | |
| GR | |
| GT | |
| GV | |
| Class H | |
| H | |
| HA | |
| HB | |
| HC | |
| HD | |
| HE | |
| HF | |
| HG | |
| HJ | |
| HM | |
| HN | |
| HQ | |
| HS | |
| HT | |
| HV | |
| HX | |
| Class J | |
| J | |
| JA | |
| JC | |
| JF | |
| JJ | |
| JK | |
| JL | |
| JN | |
| JQ | |
| JS | |
| JV | |
| JZ | |
| Class K | |
| K | |
| KB | |
| KBM | |
| KBP | |
| KBR | |
| KBU | |
| KD | |
| KDZ | |
| KE | |
| KF | |
| KG | |
| KH | |
| KJ | |
| KL | |
| KZ | |
| Class L | |
| L | |
| LA | |
| | Letter | Subject |
| LB | |
| LC | |
| LD | |
| LE | |
| LF | |
| LG | |
| LH | |
| LJ | |
| LT | |
| Class M | |
| M | |
| ML | |
| MT | |
| Class N | |
| N | |
| NA | |
| NB | |
| NC | |
| ND | |
| NE | |
| NK | |
| NX | |
| Class P | |
| P | |
| PA | |
| PB | |
| PC | |
| PD | |
| PE | |
| PF | |
| PG | |
| PH | |
| PJ | |
| PK | |
| PL | |
| PM | |
| PN | |
| PQ | |
| PR | |
| PS | |
| PT | |
| PZ | |
| Class Q | |
| Q | |
| QA | |
| QB | |
| QC | |
| QD | |
| QE | |
| QH | |
| QK | |
| QL | |
| QM | |
| QP | |
| QR | |
| Class R | |
| R | |
| RA | |
| RB | |
| RC | |
| RD | |
| | Letter | Subject |
| RE | |
| RF | |
| RG | |
| RJ | |
| RK | |
| RL | |
| RM | |
| RS | |
| RT | |
| RV | |
| RX | |
| RZ | |
| Class S | |
| S | |
| SB | |
| SD | |
| SF | |
| SH | |
| SK | |
| Class T | |
| T | |
| TA | |
| TC | |
| TD | |
| TE | |
| TF | |
| TG | |
| TH | |
| TJ | |
| TK | |
| TL | |
| TN | |
| TP | |
| TR | |
| TS | |
| TT | |
| TX | |
| Class U | |
| U | |
| UA | |
| UB | |
| UC | |
| UD | |
| UE | |
| UF | |
| UG | |
| UH | |
| Class V | |
| V | |
| VA | |
| VB | |
| VC | |
| VD | |
| VE | |
| VF | |
| VG | |
| VK | |
| VM | |
| Class Z | |
| Z | |
| ZA | |
|