diff --git a/Merlin-16-REL-Format.md b/Merlin-16-REL-Format.md
index aab5e26..bc667f9 100644
--- a/Merlin-16-REL-Format.md
+++ b/Merlin-16-REL-Format.md
@@ -12,6 +12,17 @@ This is followed by 0 or more relation records, a 0 byte, 0 or more label entrie
 
 Relocation records are 4 bytes long. The first bytes is a flag byte. This is followed by a 16-bit offset, and an 8-bit operand byte. For external references, the operand byte is the external symbol number.  For local references, the operand byte is the low 8-bits of the assembled operand.
 
+### Flag Byte
+
+* bits 0-3 always populated (`$0f`)
+* bit 4 (`$10`) indicates an external label
+* bit 7 (`$80) indicates a 2-byte relocation
+* bit 5 (`$20) indicates a 3-byte relocation
+* `$ff` indicates a shift (see below)
+
+This is followed by the 16-bit offset to patch.
+
+For external symbols, the 4th bytes is the symbol number (which starts at 0). For local symbols, the 4th byte is the low byte of the operand at the offset.
 
 ### Shifting
 
@@ -44,7 +55,7 @@ For local and EQU labels, this is the label address (based on the `$8000` origin
 For external labels, this is the external label number + `$8000`.
 
 ## References
-* Merlin 816 Macro Assembler Manual
+* Merlin 8/16 User's Manual
 * Merlin 16+ source code
 * Quick Asm source code
 * Empirical testing
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