International law in general — Sources — General principles of law — Estoppel or preclusion — Scope and meaning in international law — Substantive nature of principle — Distinction between estoppel and acquiescence — Circumstances in which acquiescence operates as estoppel — Requirement of reliance upon statements or conduct by other party — Burden of proof.

Territorial sovereignty — In general — Nature of — Disputes as to sovereignty — Judicial settlement of — Burden of proof.

Territorial sovereignty-In general — Nature of — Disputes as to sovereignty — Relinquishment of territory by treaty — Presumption in javorem ejus qui dat.

Treaties — In general — Form of international agreements — Agreement inferred from conduct — Whether delivery of maps to neighbouring State may be basis for inference as to boundary agreement.

Treaties — Operation of — Requirement of consistency in interpretation and observance.

State territory — Parts of — Boundaries — Land boundaries — Treaty providing for watershed line — Map of area subsequently published by one Party — Evidential value of maps — Effect of material errorLine on map not correct watershed line — Whether circumstances such as to put other Party on notice — Effect of acceptance of map by other Party — Acceptance based on mistaken belief that map correctly drawn — Operation of principle of acquiescence in relation to maps — Map acquiring treaty character — Effect of failure to object to map in subsequent negotiations — Relevance of administrative acts as evidence of acceptance or non — acceptanceof map — Relevance of official visit to area and flying of flag of host State — Relevance of intention to achieve finality in boundary treaty.